Power system fault and weak node analysis method, system and device and medium

Abstract

The invention relates to the field of power system dynamic analysis, and discloses a power system fault and weak node analysis method, system and device and a medium, and the method comprises the steps: calculating a transient voltage waveform under an expected fault according to a power system parameter; constructing a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the anticipated fault; establishing constraint conditions of the multi-time scale voltage dynamic characteristic quantitative index; the existence proportion of the power system nodes with the voltage dynamic characteristic quantitative indexes not meeting the constraint conditions under the expected fault is obtained; and carrying out power system fault and weak node analysis according to the existence proportion of the power system nodes which do not meet the constraint conditions. According to the invention, the node voltage stability is evaluated under different time scales, and the difference of supporting capabilities of different power electronic devices is considered.

Description

Technical Field

[0001] The present disclosure relates to the technical field of power system dynamic analysis, and in particular to a method, system, device and medium for analyzing power system faults and weak nodes. Background Art

[0002] As more and more power electronic devices are connected to the power grid, the transient characteristics of the power system undergo complex changes. In a power grid where power electronic equipment accounts for a relatively high proportion, in order to ensure the stability of the power grid, multiple types of power electronic equipment in the system will actively provide reactive power support when a system failure occurs, making the stability of the power grid more difficult to quantify and analyze. Traditional transient voltage stability weak point analysis methods usually ignore the differences in transient characteristics of different types of power electronic equipment and cannot finely study systems containing multiple types of reactive power support equipment. Summary of the invention

[0003] The embodiments of the present disclosure provide a method, system, device and medium for analyzing faults and weak nodes in a power system to solve or alleviate one or more of the above technical problems in the prior art.

[0004] According to one aspect of the present disclosure, there is provided a method for analyzing faults and weak nodes in a power system, comprising:

[0005] Calculate the transient voltage waveform under the expected fault according to the power system parameters;

[0006] Constructing a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault;

[0007] Establishing constraint conditions for the quantified index of multi-time-scale voltage dynamic characteristics;

[0008] Obtain the proportion of power system nodes whose voltage dynamic characteristic quantitative indicators do not meet the constraint conditions under the expected fault;

[0009] The power system fault and weak node analysis is performed according to the existence ratio of the power system nodes that do not meet the constraint conditions.

[0010] In a possible implementation, calculating the transient voltage waveform under a predicted fault according to the power system parameters includes:

[0011] Obtain power system parameters;

[0012] constructing a set of anticipated faults according to the power system parameters;

[0013] According to the expected fault set, simulation calculation is carried out to obtain the transient voltage waveform of each node in the power system under each expected fault.

[0014] In a possible implementation, constructing a multi-time-scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault includes:

[0015] Construct transient voltage sag component index TVSI1:

[0016]

[0017] In the formula, TVSI d 1 represents the severity index of the drop component index, which describes the extent of voltage drop during the period from when the system fails to when it is removed; TVSI c 1 indicates the qualification index of the drop component index;

[0018]

[0019] Where, T f Indicates the time when the fault occurs; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage drop component is 0; TVDI1 is the transient drop component deviation index; TVDI 1j,t represents the TVDI1 value of the jth node at time t;

[0020]

[0021] Where V j,t represents the voltage value of the jth node at time t, V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0022] In a possible implementation, constructing a multi-time-scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault includes:

[0023] Construct the transient voltage recovery component index TVSI2:

[0024]

[0025] In the formula, TVSI d 2 represents the severity index of the recovery component index, which describes the ability of the system to recover from transient voltage disturbances; TVSI c 2 represents the eligibility index of the recovery component index;

[0026]

[0027] Where, T j,2 Indicates that after the fault is cleared, the voltage of the jth bus is restored to V j,0 The moment; Tc Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage recovery component is 0; TVDI2 is the transient recovery component deviation index; TVDI 2j,t represents the TVDI2 value of the jth node at time t;

[0028]

[0029] Where V j,t represents the voltage value of the jth node at time t, V j,0 represents the bus voltage value of the jth node at the initial moment, V s It represents the stable voltage value of the bus before the fault occurs; μ is the threshold value of the unacceptable voltage deviation level.

[0030] In a possible implementation, constructing a multi-time-scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault includes:

[0031] Construct the steady-state voltage level component index TVSI3:

[0032]

[0033] In the formula, TVSI d 3 represents the severity index of the horizontal component index, which describes the ability of the system to recover to the original voltage level after the fault is cleared; TVSIc3 represents the qualification index of the horizontal component index;

[0034]

[0035] Where, T s is the moment when the bus voltage reaches a stable state after a fault; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation degree meets the rigid judgment standard of voltage safety, the qualification index in the steady-state voltage level component is 0; TVDI3 is the deviation index after voltage stabilization; TVDI 3,j It represents the TVDI3 value after the jth node reaches the steady state;

[0036]

[0037] In the formula, Represents the voltage value of the jth node after it returns to steady state; V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0038] In a possible implementation, the constraint condition of the multi-time scale voltage dynamic characteristic quantitative index is as follows:

[0039] TVSI f 1j ≤TVSI 1max

[0040] TVSI f 2j ≤TVSI 2max ,f∈S f

[0041] TVSI f 3j ≤TVSI 3max ;

[0042] In the formula, TVSI f 1j Represents the transient voltage drop component index of any node j under the expected fault f; TVSI f 2j Represents the transient voltage recovery component index of any node j under the expected fault f; TVSI f 3j Represents the steady-state voltage level component index of any node j under the expected fault f; TVSI 1max Indicates the transient voltage sag component index threshold; TVSI 2max Indicates the transient voltage recovery component index threshold; TVSI 3max Indicates the steady-state voltage level component index threshold; S f Indicates the expected fault set.

[0043] In a possible implementation, performing power system fault and weak node analysis according to the existence ratio of power system nodes that do not satisfy the constraint condition includes:

[0044] When the proportion of the power system nodes that do not meet the constraint condition is greater than a first set proportion, the corresponding fault is identified as a serious fault;

[0045] When the existence ratio of the power system nodes that do not meet the constraint conditions is less than a second set ratio, the corresponding power system node is identified as a weak node for stable operation of the power grid voltage.

[0046] According to one aspect of the present disclosure, there is provided a power system fault and weak node analysis system, comprising:

[0047] A calculation unit, used for calculating a transient voltage waveform under a predicted fault according to power system parameters;

[0048] A construction unit, used to construct a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault;

[0049] An establishing unit, used to establish the constraint conditions of the multi-time scale voltage dynamic characteristic quantitative index;

[0050] An acquisition unit, used for acquiring the existence ratio of power system nodes whose voltage dynamic characteristic quantitative index does not satisfy the constraint condition under the expected fault;

[0051] The analysis unit is used to perform power system fault and weak node analysis according to the existence ratio of power system nodes that do not meet the constraint conditions.

[0052] In a possible implementation, the computing unit includes:

[0053] An acquisition module, used for acquiring power system parameters;

[0054] A construction module, used for constructing a set of expected faults according to the power system parameters;

[0055] The simulation module is used to perform simulation calculations based on the expected fault set to obtain the transient voltage waveforms of each node in the power system under each expected fault.

[0056] In a possible implementation, the construction unit is specifically used to:

[0057] Construct transient voltage sag component index TVSI1:

[0058]

[0059] In the formula, TVSI d 1 represents the severity index of the drop component index, which describes the extent of voltage drop during the period from when the system fails to when it is removed; TVSI c 1 indicates the qualification index of the drop component index;

[0060]

[0061] Where, T f Indicates the time when the fault occurs; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage drop component is 0; TVDI1 is the transient drop component deviation index; TVDI 1j,t represents the TVDI1 value of the jth node at time t;

[0062]

[0063] Where V j,t represents the voltage value of the jth node at time t, V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0064] In a possible implementation, the construction unit is specifically used to:

[0065] Construct the transient voltage recovery component index TVSI2:

[0066]

[0067] In the formula, TVSI d 2 represents the severity index of the recovery component index, which describes the ability of the system to recover from transient voltage disturbances; TVSI c 2 represents the eligibility index of the recovery component index;

[0068]

[0069] Where, T j,2 Indicates that after the fault is cleared, the voltage of the jth bus is restored to V j,0 The moment; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage recovery component is 0; TVDI2 is the transient recovery component deviation index; TVDI 2j,t represents the TVDI2 value of the jth node at time t;

[0070]

[0071] Where V j,t represents the voltage value of the jth node at time t, V j,0 represents the bus voltage value of the jth node at the initial moment, V s It represents the stable voltage value of the bus before the fault occurs; μ is the threshold value of the unacceptable voltage deviation level.

[0072] In a possible implementation, the construction unit is specifically used to:

[0073] Construct the steady-state voltage level component index TVSI3:

[0074]

[0075] In the formula, TVSI d 3 represents the severity index of the horizontal component index, which describes the ability of the system to recover to the original voltage level after the fault is cleared; TVSIc3 represents the qualification index of the horizontal component index;

[0076]

[0077] Where, T sis the moment when the bus voltage reaches a stable state after a fault; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation degree meets the rigid judgment standard of voltage safety, the qualification index in the steady-state voltage level component is 0; TVDI3 is the deviation index after voltage stabilization; TVDI 3,j It represents the TVDI3 value after the jth node reaches the steady state;

[0078]

[0079] Where V j,Ts Represents the voltage value of the jth node after it returns to steady state; V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0080] In a possible implementation, the constraint condition of the multi-time scale voltage dynamic characteristic quantitative index is as follows:

[0081] TVSI f 1j ≤TVSI 1max

[0082] TVSI f 2j ≤TVSI 2max ,f∈S f

[0083] TVSI f 3j ≤TVSI 3max ;

[0084] In the formula, TVSI f 1j Represents the transient voltage drop component index of any node j under the expected fault f; TVSI f 2j Represents the transient voltage recovery component index of any node j under the expected fault f; TVSI f 3j Represents the steady-state voltage level component index of any node j under the expected fault f; TVSI 1max Indicates the transient voltage sag component index threshold; TVSI 2max Indicates the transient voltage recovery component index threshold; TVSI 3max Indicates the steady-state voltage level component index threshold; S f Indicates the expected fault set.

[0085] In a possible implementation, the analysis unit includes:

[0086] A first identification module, configured to identify a corresponding fault as a serious fault when the proportion of the power system nodes that do not satisfy the constraint condition is greater than a first set proportion;

[0087] The second identification module is used to identify the corresponding power system node as a weak node for stable operation of power grid voltage when the existence ratio of the power system nodes that do not meet the constraint conditions is less than a second set ratio.

[0088] According to one aspect of the present disclosure, there is provided a device, comprising:

[0089] Processor and memory;

[0090] The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute any one of the above-mentioned methods for analyzing power system faults and weak nodes.

[0091] According to one aspect of the present disclosure, a computer-readable storage medium is provided, in which a computer program is stored. When the computer program is executed by a processor, the processor is enabled to execute any of the above-mentioned methods for analyzing power system faults and weak nodes.

[0092] The present disclosure has the following beneficial effects: the present disclosure divides the node voltage dynamic process of the power system into three stages, namely, the voltage drop stage, the voltage recovery stage and the stable voltage change stage, and quantitatively analyzes each stage through multi-time scale voltage dynamic characteristic quantitative indicators. Specifically, a transient voltage drop component index is designed for the voltage drop stage, a transient voltage recovery component index is designed for the voltage recovery stage, and a steady-state voltage level component index is designed for the stable voltage change stage, thereby realizing the evaluation of node voltage stability at different time scales, taking into account the differences in the supporting capabilities of different power electronic equipment. In addition, for the node voltage dynamics at different stages, indicators that can correctly evaluate the transient voltage stability of the node are designed, so that a more refined transient voltage stability judgment can be made.

[0093] The details of one or more embodiments of the present disclosure are presented in the following drawings and descriptions. Other features and advantages of the present disclosure will become apparent from the accompanying drawings. It should be understood that the above general description and the detailed description below are only exemplary and explanatory and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification are used to explain the principles of the present disclosure. Obviously, the accompanying drawings described below are only some embodiments of the present disclosure, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0095] Figure 1 is one of the flow charts of a method for analyzing faults and weak nodes in a power system of the present exemplary embodiment;

[0096] Figure 2 This is a second flow chart of a method for analyzing power system faults and weak nodes according to the exemplary embodiment;

[0097] Figure 3 is a block diagram of a power system fault and weak node analysis system of the present exemplary embodiment;

[0098] Figure 4 It is a schematic structural diagram of a device of this exemplary embodiment. DETAILED DESCRIPTION

[0099] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as being limited to the examples set forth herein; on the contrary, these embodiments are provided so that the present disclosure will be more comprehensive and complete, and the concepts of the example embodiments are fully conveyed to those skilled in the art. The described features, structures, or characteristics may be combined in one or more embodiments in any suitable manner. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known technical solutions are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0100] In addition, the accompanying drawings are only schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the figures represent the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in software form, or implemented in one or more hardware units or integrated circuits, or implemented in different networks and / or processor devices and / or microcontroller devices.

[0101] The flowcharts shown in the accompanying drawings are only exemplary and do not necessarily include all the steps. For example, some steps may be decomposed, while some steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0102] The terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments of the present disclosure described herein can, for example, be implemented in an order other than those illustrated or described herein.

[0103] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or sub-modules is not necessarily limited to those steps or sub-modules explicitly listed, but may include other steps or sub-modules not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0104] Figure 1 is one of the flow charts of a method for analyzing power system faults and weak nodes of this exemplary embodiment, such as Figure 1 As shown, an exemplary embodiment of the present disclosure provides a method for analyzing faults and weak nodes in a power system, comprising:

[0105] Calculate the transient voltage waveform under the expected fault according to the power system parameters;

[0106] Constructing a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault;

[0107] Establishing constraint conditions for the quantified index of multi-time-scale voltage dynamic characteristics;

[0108] Obtain the proportion of power system nodes whose voltage dynamic characteristic quantitative indicators do not meet the constraint conditions under the expected fault;

[0109] The power system fault and weak node analysis is performed according to the existence ratio of the power system nodes that do not meet the constraint conditions.

[0110] This embodiment comprehensively considers the response characteristics of different power electronic devices and proposes a method for identifying weak points of transient voltage stability under multiple time scales. First, simulation is performed based on the expected fault set of the system to obtain the transient voltage curve of the power electronic device under each fault; then quantitative indicators of node voltage dynamic characteristics at multiple time scales are proposed and calculated; finally, a method for identifying weak points of transient voltage is constructed by combining the quantitative indicators and the threshold set according to the expected fault set.

[0111] Specifically, the transient voltage waveform under the expected fault is calculated according to the power system parameters, including:

[0112] Obtain power system parameters;

[0113] constructing a set of anticipated faults according to the power system parameters;

[0114] According to the expected fault set, simulation calculation is carried out to obtain the transient voltage waveform of each node in the power system under each expected fault.

[0115] like Figure 2 As shown, the transient voltage stability weak point identification method considering multiple time scales proposed in this embodiment includes the following steps:

[0116] (1) Calculate the transient voltage waveform under the expected fault according to the power system parameters: Construct the expected fault set according to the power system parameters and calculate the transient voltage waveform of each node under the expected fault.

[0117] (2) Constructing multi-time scale voltage dynamic characteristics quantitative indicators: Propose multi-time scale voltage dynamic characteristics quantitative indicators to quantitatively analyze the voltage drop process, voltage recovery process and stable voltage change process respectively. Each component contains a qualification indicator and a severity indicator.

[0118] 1) Transient voltage drop component index:

[0119] In the voltage drop process from the fault moment to the fault removal, the transient voltage drop component index is defined as follows:

[0120]

[0121] Among them, TVSI d 1 represents the severity index of the drop component index, which describes the extent of voltage drop during the period from when the system fails to when it is removed; TVSI c 1 represents the qualification index of the drop component index. The specific meaning is as follows:

[0122]

[0123] Among them, T f is the fault occurrence time, T c is the fault clearing time, N is the number of all buses in the system. M is an arbitrary constant that is much larger than 1. Only when the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the component is 0. TVDI1 (Transient Voltage Deviation Index) is the transient drop component deviation index, TVDI 1j,t represents the TVDI1 value of the jth node at time t, which is calculated as follows:

[0124]

[0125] Among them, V j,t represents the voltage value of the jth node at time t, V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0126] 2) Transient voltage recovery component index:

[0127] Similarly, during the voltage recovery process after the fault is cleared, the transient voltage severity index is defined as follows:

[0128]

[0129] Among them, TVSI d 2 represents the severity index of the recovery component index, which describes the ability of the system to recover from transient voltage disturbances; TVSI c 2 represents the qualification index of the recovery component index. The specific meaning is as follows:

[0130]

[0131] Where, T j,2 Indicates that after the fault is cleared, the voltage of the jth bus is restored to V j,0 The moment; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1; TVDI2 is the transient recovery component deviation index, TVDI 2j,t represents the TVDI2 value of the jth node at time t, which is calculated as follows:

[0132]

[0133] Where V j,t represents the voltage value of the jth node at time t, V j,0 represents the bus voltage value of the jth node at the initial moment, V s It represents the stable voltage value of the bus before the fault occurs; μ is the threshold value of the unacceptable voltage deviation level.

[0134] 3) Steady-state voltage level component index:

[0135] In the voltage stable state after the fault is stabilized, the steady-state voltage level component index is defined as follows:

[0136]

[0137] Among them, TVSI d3 represents the severity index of the horizontal component index, which describes the ability of the system to restore to the original voltage level after the fault is cleared; TVSIc3 represents the qualification index of the horizontal component index. The specific meaning is as follows:

[0138]

[0139] Among them, T s is the moment when the bus voltage reaches a stable state after the fault. N is the number of all buses in the system. TVDI3 is the deviation index after voltage stabilization, TVDI 3,j It represents the TVDI3 value after the jth node reaches the steady state, which is calculated as follows:

[0140]

[0141] In the formula, Represents the voltage value of the jth node after it returns to steady state; V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0142] This embodiment divides the dynamic process of node voltage in the power system into three stages, namely, the voltage drop stage from the moment of fault to fault removal, the voltage recovery stage after fault clearance, and the voltage stable state stage after the fault is stabilized. The node voltage stability is evaluated at different time scales, taking into account the differences in the supporting capabilities of different power electronic equipment. This embodiment also designs indicators that can correctly evaluate the transient voltage stability of the node for the node voltage dynamics at different stages, and makes a more refined transient voltage stability judgment.

[0143] (3) Calculate the voltage stability weaknesses at multiple time scales based on the expected fault set: For a system with strong voltage stability, the TVSI index of any node j should satisfy the following constraints:

[0144]

[0145] Among them, the thresholds of TVSI index components at each time scale should be set according to the requirements, and the superscript f represents the fault set S f If there are nodes in the system whose TVSI index does not meet the constraints under fault f and the proportion exceeds a certain proportion (i.e., the first set proportion), the fault is considered a serious fault; if there are nodes in the system whose TVSI index does not meet the constraints under fault f but the proportion is less than a certain proportion (i.e., the second set proportion), the nodes are weak nodes for stable operation of grid voltage.

[0146] Figure 3 is a block diagram of a power system fault and weak node analysis system of the present exemplary embodiment, such as Figure 3As shown, an exemplary embodiment of the present disclosure provides a power system fault and weak node analysis system, comprising:

[0147] A calculation unit, used for calculating a transient voltage waveform under a predicted fault according to power system parameters;

[0148] A construction unit, used to construct a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault;

[0149] An establishing unit, used to establish the constraint conditions of the multi-time scale voltage dynamic characteristic quantitative index;

[0150] An acquisition unit, used for acquiring the existence ratio of power system nodes whose voltage dynamic characteristic quantitative index does not satisfy the constraint condition under the expected fault;

[0151] The analysis unit is used to perform power system fault and weak node analysis according to the existence ratio of power system nodes that do not meet the constraint conditions.

[0152] In a possible implementation, the computing unit includes:

[0153] An acquisition module, used for acquiring power system parameters;

[0154] A construction module, used for constructing a set of expected faults according to the power system parameters;

[0155] The simulation module is used to perform simulation calculations based on the expected fault set to obtain the transient voltage waveforms of each node in the power system under each expected fault.

[0156] In a possible implementation, the construction unit is specifically used to:

[0157] Construct transient voltage sag component index TVSI1:

[0158]

[0159] In the formula, TVSI d 1 represents the severity index of the drop component index, which describes the extent of voltage drop during the period from when the system fails to when it is removed; TVSI c 1 indicates the qualification index of the drop component index;

[0160]

[0161] Where, T f Indicates the time when the fault occurs; T cIndicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage drop component is 0; TVDI1 is the transient drop component deviation index; TVDI 1j,t represents the TVDI1 value of the jth node at time t;

[0162]

[0163] Where V j,t represents the voltage value of the jth node at time t, V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0164] In a possible implementation, the construction unit is specifically used to:

[0165] Construct the transient voltage recovery component index TVSI2:

[0166]

[0167] In the formula, TVSI d 2 represents the severity index of the recovery component index, which describes the ability of the system to recover from transient voltage disturbances; TVSI c 2 represents the eligibility index of the recovery component index;

[0168]

[0169] Where, T j,2 Indicates that after the fault is cleared, the voltage of the jth bus is restored to V j,0 The moment; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage recovery component is 0; TVDI2 is the transient recovery component deviation index; TVDI 2j,t represents the TVDI2 value of the jth node at time t;

[0170]

[0171] Where V j,t represents the voltage value of the jth node at time t, V j,0 represents the bus voltage value of the jth node at the initial moment, V s It represents the stable voltage value of the bus before the fault occurs; μ is the threshold value of the unacceptable voltage deviation level.

[0172] In a possible implementation, the construction unit is specifically used to:

[0173] Construct the steady-state voltage level component index TVSI3:

[0174]

[0175] In the formula, TVSI d 3 represents the severity index of the horizontal component index, which describes the ability of the system to recover to the original voltage level after the fault is cleared; TVSIc3 represents the qualification index of the horizontal component index;

[0176]

[0177] Where, T s is the moment when the bus voltage reaches a stable state after a fault; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation degree meets the rigid judgment standard of voltage safety, the qualification index in the steady-state voltage level component is 0; TVDI3 is the deviation index after voltage stabilization; TVDI 3,j It represents the TVDI3 value after the jth node reaches the steady state;

[0178]

[0179] In the formula, Represents the voltage value of the jth node after it returns to steady state; V j,0 Represents the bus voltage value of the jth node at the initial moment.

[0180] In a possible implementation, the constraint condition of the multi-time scale voltage dynamic characteristic quantitative index is as follows:

[0181] TVSI f 1j ≤TVSI 1max

[0182] TVSI f 2j ≤TVSI 2max ,f∈S f

[0183] TVSI f 3j ≤TVSI 3max ;

[0184] In the formula, TVSI f 1j Represents the transient voltage drop component index of any node j under the expected fault f; TVSI f 2j Represents the transient voltage recovery component index of any node j under the expected fault f; TVSI f 3jRepresents the steady-state voltage level component index of any node j under the expected fault f; TVSI 1max Indicates the transient voltage sag component index threshold; TVSI 2max Indicates the transient voltage recovery component index threshold; TVSI 3max Indicates the steady-state voltage level component index threshold; S f Indicates the expected fault set.

[0185] In a possible implementation, the analysis unit includes:

[0186] A first identification module, configured to identify a corresponding fault as a serious fault when the proportion of the power system nodes that do not satisfy the constraint condition is greater than a first set proportion;

[0187] The second identification module is used to identify the corresponding power system node as a weak node for stable operation of power grid voltage when the existence ratio of the power system nodes that do not meet the constraint conditions is less than a second set ratio.

[0188] Figure 4 Schematic diagram of the structure of a device of this exemplary embodiment. Figure 4 As shown, corresponding to the above-mentioned power system fault and weak node analysis method, the present disclosure also provides a device. Since the embodiment of the device is similar to the above-mentioned method embodiment, the description is relatively simple. For relevant parts, please refer to the description of the above-mentioned method embodiment part. The device described below is only schematic. The device may include: a processor (processor) 1, a memory (memory) 2 and a communication bus (i.e., the above-mentioned device bus) and a search engine, wherein the processor 1 and the memory 2 complete mutual communication through the communication bus and communicate with the outside through the communication interface. The processor 1 can call the logic instructions in the memory 2 to execute the power system fault and weak node analysis method.

[0189] In addition, the logic instructions in the above-mentioned memory 2 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present disclosure is essentially or the part that contributes to the prior art or the part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present disclosure. The aforementioned storage medium includes: a storage chip, a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a disk or an optical disk, and other media that can store program codes.

[0190] On the other hand, an embodiment of the present disclosure further provides a processor-readable storage medium, on which a computer program 3 is stored. When the computer program 3 is executed by the processor 1, it is implemented to execute the power system fault and weak node analysis method provided in the above embodiments.

[0191] The processor-readable storage medium can be any available medium or data storage device that can be accessed by the processor 1, including but not limited to magnetic storage (such as floppy disks, hard disks, magnetic tapes, magneto-optical disks (MO), etc.), optical storage (such as CD, DVD, BD, HVD, etc.), and semiconductor storage (such as ROM, EPROM, EEPROM, non-volatile memory (NANDFLASH), solid-state drive (SSD)), etc.

[0192] The above are only preferred implementations of the present disclosure, and the protection scope of the present disclosure is not limited to the above embodiments. All technical solutions under the concept of the present disclosure belong to the protection scope of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present disclosure should be regarded as the protection scope of the present disclosure.

Claims

1. A method for analyzing power system faults and weak nodes, characterized in that: include: Calculate the transient voltage waveform under the expected fault according to the power system parameters; Constructing a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault; Establishing constraint conditions for the quantified index of multi-time-scale voltage dynamic characteristics; Obtain the proportion of power system nodes whose voltage dynamic characteristic quantitative indicators do not meet the constraint conditions under the expected fault; The power system fault and weak node analysis is performed according to the existence ratio of the power system nodes that do not meet the constraint conditions.

2. The method for analyzing power system faults and weak nodes according to claim 1, characterized in that: Calculate the transient voltage waveform under expected fault conditions based on power system parameters, including: Obtain power system parameters; constructing a set of anticipated faults according to the power system parameters; According to the expected fault set, simulation calculation is carried out to obtain the transient voltage waveform of each node in the power system under each expected fault.

3. The method for analyzing power system faults and weak nodes according to claim 1, characterized in that: Based on the transient voltage waveform under the expected fault, a multi-time scale voltage dynamic characteristic quantitative index is constructed, including: Construct transient voltage sag component index TVSI1: In the formula, TVSI d 1 represents the severity index of the drop component index, which describes the extent of voltage drop during the period from when the system fails to when it is removed; TVSI c 1 indicates the qualification index of the drop component index; Where, T f Indicates the time when the fault occurs; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage drop component is 0; TVDI1 is the transient drop component deviation index; TVDI 1j,t represents the TVDI1 value of the jth node at time t; Where V j,t represents the voltage value of the jth node at time t, V j,0 Represents the bus voltage value of the jth node at the initial moment.

4. The method for analyzing power system faults and weak nodes according to claim 1, characterized in that: Based on the transient voltage waveform under the expected fault, a multi-time scale voltage dynamic characteristic quantitative index is constructed, including: Construct the transient voltage recovery component index TVSI2: In the formula, TVSI d 2 represents the severity index of the recovery component index, which describes the ability of the system to recover from transient voltage disturbances; TVSI c 2 represents the eligibility index of the recovery component index; Where, T j,2 Indicates that after the fault is cleared, the voltage of the jth bus is restored to V j,0 The moment; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage recovery component is 0; TVDI2 is the transient recovery component deviation index; TVDI 2j,t represents the TVDI2 value of the jth node at time t; Where V j,t represents the voltage value of the jth node at time t, V j,0 represents the bus voltage value of the jth node at the initial moment, V s It represents the stable voltage value of the bus before the fault occurs; μ is the threshold value of the unacceptable voltage deviation level.

5. The method for analyzing power system faults and weak nodes according to claim 1, characterized in that: Based on the transient voltage waveform under the expected fault, a multi-time scale voltage dynamic characteristic quantitative index is constructed, including: Construct the steady-state voltage level component index TVSI3: In the formula, TVSI d 3 represents the severity index of the horizontal component index, which describes the ability of the system to recover to the original voltage level after the fault is cleared; TVSIc3 represents the qualification index of the horizontal component index; Where, T s is the moment when the bus voltage reaches a stable state after a fault; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation degree meets the rigid judgment standard of voltage safety, the qualification index in the steady-state voltage level component is 0; TVDI3 is the deviation index after voltage stabilization; TVDI 3,j It represents the TVDI3 value after the jth node reaches the steady state; In the formula, Represents the voltage value of the jth node after it returns to steady state; V j,0 Represents the bus voltage value of the jth node at the initial moment.

6. The method for analyzing power system faults and weak nodes according to claim 1, characterized in that: The constraint condition of the multi-time scale voltage dynamic characteristic quantitative index is as follows: TVSI f 1j ≤TVSI 1max TVSI f 2j ≤TVSI 2max ,f∈S f TVSI f 3j ≤TVSI 3max ; In the formula, TVSI f 1j Represents the transient voltage drop component index of any node j under the expected fault f; TVSI f 2j Represents the transient voltage recovery component index of any node j under the expected fault f; TVSI f 3j Represents the steady-state voltage level component index of any node j under the expected fault f; TVSI 1max Indicates the transient voltage sag component index threshold; TVSI 2max Indicates the transient voltage recovery component index threshold; TVSI 3max Indicates the steady-state voltage level component index threshold; S f Indicates the expected fault set.

7. The method for analyzing power system faults and weak nodes according to claim 1, characterized in that: Performing power system fault and weak node analysis according to the existence ratio of power system nodes that do not meet the constraint conditions includes: When the proportion of the power system nodes that do not meet the constraint condition is greater than a first set proportion, the corresponding fault is identified as a serious fault; When the existence ratio of the power system nodes that do not meet the constraint conditions is less than a second set ratio, the corresponding power system node is identified as a weak node for stable operation of the power grid voltage.

8. A power system fault and weak node analysis system, characterized in that: include: A calculation unit, used for calculating a transient voltage waveform under a predicted fault according to power system parameters; A construction unit, used to construct a multi-time scale voltage dynamic characteristic quantitative index based on the transient voltage waveform under the expected fault; An establishing unit, used to establish the constraint conditions of the multi-time scale voltage dynamic characteristic quantitative index; An acquisition unit, used for acquiring the existence ratio of power system nodes whose voltage dynamic characteristic quantitative index does not satisfy the constraint condition under the expected fault; The analysis unit is used to perform power system fault and weak node analysis according to the existence ratio of power system nodes that do not meet the constraint conditions.

9. The power system fault and weak node analysis system according to claim 8, characterized in that: The computing unit includes: An acquisition module, used for acquiring power system parameters; A construction module, used for constructing a set of expected faults according to the power system parameters; The simulation module is used to perform simulation calculations based on the expected fault set to obtain the transient voltage waveforms of each node in the power system under each expected fault.

10. The power system fault and weak node analysis system according to claim 8, characterized in that: The building blocks are specifically used for: Construct transient voltage sag component index TVSI1: In the formula, TVSI d 1 represents the severity index of the drop component index, which describes the extent of voltage drop during the period from when the system fails to when it is removed; TVSI c 1 indicates the qualification index of the drop component index; Where, T f Indicates the time when the fault occurs; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage drop component is 0; TVDI1 is the transient drop component deviation index; TVDI 1j,t represents the TVDI1 value of the jth node at time t; Where V j,t represents the voltage value of the jth node at time t, V j,0 Represents the bus voltage value of the jth node at the initial moment.

11. The power system fault and weak node analysis system according to claim 8, characterized in that: The building blocks are specifically used for: Construct the transient voltage recovery component index TVSI2: In the formula, TVSI d 2 represents the severity index of the recovery component index, which describes the ability of the system to recover from transient voltage disturbances; TVSI c 2 represents the eligibility index of the recovery component index; Where, T j,2 Indicates that after the fault is cleared, the voltage of the jth bus is restored to V j,0 The moment; T c Indicates the fault clearing time; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation level meets the rigid judgment standard of voltage safety, the qualification index in the transient voltage recovery component is 0; TVDI2 is the transient recovery component deviation index; TVDI 2j,t represents the TVDI2 value of the jth node at time t; Where V j,t represents the voltage value of the jth node at time t, V j,0 represents the bus voltage value of the jth node at the initial moment, V s It represents the stable voltage value of the bus before the fault occurs; μ is the threshold value of the unacceptable voltage deviation level.

12. The power system fault and weak node analysis system according to claim 8, characterized in that: The building blocks are specifically used for: Construct the steady-state voltage level component index TVSI3: In the formula, TVSI d 3 represents the severity index of the horizontal component index, which describes the ability of the system to recover to the original voltage level after the fault is cleared; TVSIc3 represents the qualification index of the horizontal component index; Where, T s is the moment when the bus voltage reaches a stable state after a fault; N is the number of all buses in the system; M is an arbitrary constant that is much larger than 1. When the voltage fluctuation degree meets the rigid judgment standard of voltage safety, the qualification index in the steady-state voltage level component is 0; TVDI3 is the deviation index after voltage stabilization; TVDI 3,j It represents the TVDI3 value after the jth node reaches the steady state; In the formula, Represents the voltage value of the jth node after it returns to steady state; V j,0 Represents the bus voltage value of the jth node at the initial moment.

13. The power system fault and weak node analysis system according to claim 8, characterized in that: The constraint condition of the multi-time scale voltage dynamic characteristic quantitative index is as follows: TVSI f 1j ≤TVSI 1max TVSI f 2j ≤TVSI 2max ,f∈S f TVSI f 3j ≤TVSI 3max ; In the formula, TVSI f 1j Represents the transient voltage drop component index of any node j under the expected fault f; TVSI f 2j Represents the transient voltage recovery component index of any node j under the expected fault f; TVSI f 3j Represents the steady-state voltage level component index of any node j under the expected fault f; TVSI 1max Indicates the transient voltage sag component index threshold; TVSI 2max Indicates the transient voltage recovery component index threshold; TVSI 3max Indicates the steady-state voltage level component index threshold; S f Indicates the expected fault set.

14. The power system fault and weak node analysis system according to claim 8, characterized in that: Analysis unit, including: A first identification module, configured to identify a corresponding fault as a serious fault when the proportion of the power system nodes that do not satisfy the constraint condition is greater than a first set proportion; The second identification module is used to identify the corresponding power system node as a weak node for stable operation of power grid voltage when the existence ratio of the power system nodes that do not meet the constraint conditions is less than a second set ratio.

15. A device, characterized in that include: Processor and memory; The memory is used to store a computer program, and the processor calls the computer program stored in the memory to execute the power system fault and weak node analysis method according to any one of claims 1 to 7.

16. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the processor is enabled to execute the power system fault and weak node analysis method according to any one of claims 1 to 7.

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