Power grid frequency safety early warning device

Abstract

The invention discloses a power grid frequency safety early warning device, which relates to the technical field of electric power and comprises a data acquisition system, a frequency vulnerability evaluation system, a power grid frequency safety early warning system and a power grid frequency safety early warning system, the early warning system is used for sending out early warning information according to an evaluation result of the frequency vulnerability evaluation system; the safety protection system is used for carrying out safety protection on the power grid according to the early warning information sent by the early warning system; the advantages of the energy management system, the phasor measurement unit and the stability control device can be combined, rapid calculation and decision support can be carried out by using real-time data of the power grid, and immediate response measures can be provided.

Description

Technical Field

[0001] The present invention relates to the field of electric power technology, and in particular to a power grid frequency safety early warning device. Background Art

[0002] The safe and stable operation of the power grid is related to the national economy, people's livelihood and national security. In recent years, large-scale power outages that have occurred frequently at home and abroad have attracted widespread attention. With the gradual expansion of power grid capacity and scale, in order to enhance the robustness of the power grid, the power grid system has been continuously modernized through highly structured and optimal design. However, while the complex power grid system has stronger robustness, it also increases its vulnerability, which further affects the safety of the power grid. Studies have shown that large-scale power outages are often caused by chain reactions of faults, and in the expansion and development stage of the accident, the vulnerable links in the power grid play a key role.

[0003] Frequency is an important parameter of the power system. It reflects the supply and demand balance of the entire system. The stability of the grid frequency is directly related to the safety and reliability of the power system. Once the frequency deviates from the normal range, it may lead to serious consequences such as equipment damage and system collapse. Therefore, real-time monitoring and early warning of grid frequency anomalies are crucial to ensure the safe and stable operation of the grid.

[0004] Existing monitoring and early warning of power grid frequency mostly rely on energy management systems, phasor measurement units or stability control devices alone. However, energy management systems mainly rely on online static analysis and lack effective evaluation of transient stability, voltage stability and dynamic stability of power grids. There are certain limitations in the frequency stability evaluation of phasor measurement units. Although stability control devices can improve the safety of the system to a certain extent, their functions are relatively single and cannot fully cover the needs of frequency stability evaluation.

[0005] In addition, some other existing early warning systems mostly use offline decision-making technology. The generated control strategy table has high dimension and large data volume, and the calculation and modification workload is huge. When the system is slightly complicated, the combination of wiring method, flow method and possible fault mode will reach a very large value, making it difficult for the system to adapt to the ever-changing actual operation. Summary of the invention

[0006] In order to overcome the shortcomings of the background technology, the present invention discloses a power grid frequency safety early warning device, which can combine the advantages of energy management system, phasor measurement unit and stability control device, use real-time data of the power grid for rapid calculation and decision support, and provide immediate response measures.

[0007] To achieve the above object, the present invention adopts the following technical solution:

[0008] A power grid frequency safety early warning device, comprising:

[0009] Data acquisition system, used to collect power grid operation parameters in real time;

[0010] Frequency vulnerability assessment system, which evaluates the grid frequency stability based on the collected data;

[0011] The early warning system issues early warning information based on the assessment results of the frequency vulnerability assessment system;

[0012] The safety protection system is used to provide safety protection for the power grid based on the warning information issued by the early warning system.

[0013] Furthermore, the data acquisition system includes a data acquisition module for acquiring real-time data of the power grid from the energy management system, the phasor measurement unit and the stability control device.

[0014] Furthermore, the frequency vulnerability assessment system includes:

[0015] A model building module is used to construct a topological network model that reflects the frequency characteristics of the power grid;

[0016] An index determination module is used to define a series of evaluation indexes reflecting frequency stability;

[0017] The vulnerability assessment module is used to establish a network model of module components according to the model, and to assess the stability of the power grid frequency based on the evaluation indicators defined by the indicator determination module.

[0018] Furthermore, the model building module represents the power grid structure as a topological network G(U,L), where U={U1,U2,…,UN} is a node set, U represents a substation, and N represents the number of nodes; L={L1,L2,…,LM} is an edge set, L represents a transmission line set, and M represents the number of transmission lines.

[0019] Furthermore, the indicator determination module includes:

[0020] A first evaluation index determination submodule, used to determine a first evaluation index reflecting the frequency deviation;

[0021] A second evaluation index determination submodule, used to determine a second evaluation index reflecting the frequency change rate;

[0022] The comprehensive evaluation index determination submodule is used to determine the comprehensive evaluation index of the power grid according to the first evaluation index and the second evaluation index.

[0023] Furthermore, the vulnerability assessment module includes:

[0024] The first evaluation submodule is used to evaluate the frequency stability of the power grid by randomly removing a certain proportion of nodes to simulate faults and analyze the impact on frequency stability;

[0025] The second evaluation submodule is used to conduct a secondary evaluation of the grid frequency stability, remove important nodes based on the node characteristic parameters, and further evaluate the frequency vulnerability.

[0026] Furthermore, the early warning system includes:

[0027] An early warning module is used to send early warning information to the user terminal;

[0028] A communication module, used to establish a data connection between the early warning module and the user terminal;

[0029] User terminal, used to receive warning information.

[0030] Furthermore, the safety protection system includes:

[0031] The automatic execution control strategy module is used to adjust the load and dispatch the power generation of the power grid to maintain the stability of the power grid frequency.

[0032] Furthermore, a warning method of a power grid frequency safety warning device comprises the following steps:

[0033] Step 1: Collect real-time data of the power grid, including:

[0034] Use data acquisition systems to obtain real-time grid operation parameters from energy management systems, phasor measurement units, and stability control devices;

[0035] Step 2: Build a model and define indicators, including:

[0036] a. Construct a power grid structure model and use the model building module to build the power grid structure model;

[0037] b. Define frequency stability evaluation indicators, including:

[0038] The first evaluation index, response frequency deviation, is calculated as follows:

[0039]

[0040] Among them, Z1 represents the first evaluation index, N 1 The number of nodes in the power grid after the surface fault occurs,

[0041] N represents the number of nodes in the power grid at the initial moment;

[0042] The second evaluation index reflects the frequency change rate, and the calculation formula is:

[0043]

[0044] Among them, Z2 represents the second evaluation index, F l represents the transmission power of line l, D 1 represents the power grid after the fault occurs, and D represents the power grid at the initial moment;

[0045] The comprehensive evaluation index, combined with the first evaluation index and the second evaluation index, is calculated as follows:

[0046] Z=αZ1+βZ2

[0047] Among them, Z represents the comprehensive evaluation index, α and β are weight coefficients;

[0048] Step 3: Frequency vulnerability assessment, including:

[0049] a. An assessment, including:

[0050] a1. Calculate the initial value of the comprehensive evaluation index of the power grid;

[0051] a2. Randomly remove a certain proportion of nodes, recalculate the comprehensive evaluation index of the power grid, and obtain the relationship between the proportion of removed nodes and the change of the comprehensive evaluation index of the power grid;

[0052] a3. Evaluate the frequency stability of the power grid according to the changes in the comprehensive evaluation indicators of the power grid and obtain an evaluation result;

[0053] b. Secondary evaluation, including:

[0054] b1. Calculate the characteristic parameters of the node:

[0055]

[0056] Among them, S i represents the characteristic parameter of node i, ρ jk represents the number of all shortest paths from node j to node k, ρ jk (i) represents the number of all shortest paths from node j to node k that pass through node i;

[0057] b2. Sort the nodes according to their characteristic parameters from large to small, remove a certain proportion of nodes, and recalculate the comprehensive evaluation index of the power grid;

[0058] b3. Obtain the relationship between the ratio of removed nodes and the change of comprehensive evaluation index of the power grid, evaluate the frequency stability of the power grid according to the change of comprehensive evaluation index of the power grid, and obtain the secondary evaluation result;

[0059] Step 4: Generate and send warning information, including:

[0060] a. The early warning module generates early warning information. When the frequency vulnerability assessment results show potential risks, the early warning module generates early warning information;

[0061] b. The communication module establishes a connection and sends warning information. The communication module establishes a data connection between the warning module and the user terminal;

[0062] c. The user terminal receives and displays the warning information, and the operator responds according to the warning information;

[0063] Step 5: Implement safety protection measures and automatically execute corresponding control strategies based on early warning conditions.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The present invention can combine the advantages of energy management systems, phasor measurement units and stability control devices, use real-time data from the power grid to perform rapid calculations and decision support, and realize intelligent prediction and analysis of power grid frequency. At the same time, it can also perform multi-level coordination based on the prediction results to enhance the flexibility and robustness of the overall system. The present invention reduces manual intervention and the workload of operation and maintenance personnel through automated prediction, analysis and early warning, thereby greatly improving the accuracy and timeliness of power grid frequency early warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a module diagram of the present invention; DETAILED DESCRIPTION

[0067] The technical solution of the present invention will be described below in conjunction with the drawings in the embodiments of the present invention. In the description, it should be understood that if there are terms such as "upper", "lower", "front", "back", "left", "right", etc. indicating directions or positional relationships, they only correspond to the drawings of the present invention and are for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific direction.

[0068] Please refer to the instruction manual Figure 1 ,The present invention provides a technical solution, a power grid frequency safety early warning device, including: a data acquisition system for real-time acquisition of power grid operation parameters, specifically, the data acquisition system includes a data acquisition module for acquiring real-time data of the power grid from an energy management system, a phasor measurement unit and a stability control device;

[0069] The data collection for the energy management system is done by configuring the CIM (Common Information Model) interface in the energy management system or using custom-developed interface software to subscribe to the required grid operation parameters, such as frequency, voltage, current, etc., through the SCADA system;

[0070] Data acquisition for phasor measurement units is achieved by configuring the phasor measurement unit device to perform synchronized phasor measurement in accordance with the IEEE C37.118 standard and communicating with the data acquisition subsystem via TCP / IP or UDP protocol. If multiple phasor measurement unit devices are connected to a WAMS master station, high-precision phasor data is obtained directly from the WAMS master station.

[0071] Data collection for the stability control device is based on the communication protocol of the stability control device (such as IEC 61850, MODBUS or DNP3), configures the communication between the data acquisition subsystem and the device, and transmits the local monitoring data to the frequency vulnerability assessment system through the field data transmission module (such as Ethernet, optical fiber or wireless communication module);

[0072] The frequency vulnerability assessment system evaluates the power grid frequency stability based on the collected data. Specifically, the frequency vulnerability assessment system includes:

[0073] The model building module is used to construct a topological network model that reflects the frequency characteristics of the power grid. Specifically, the power grid structure is represented as a topological network G(U,L), where U = {U1, U2, ..., UN} is a node set, U represents a substation, and N represents the number of nodes; L = {L1, L2, ..., LM} is an edge set, L represents a transmission line set, and M represents the number of transmission lines;

[0074] The indicator determination module is used to define a series of evaluation indicators that reflect frequency stability, including:

[0075] A first evaluation index determination submodule, used to determine a first evaluation index reflecting a frequency deviation;

[0076] A second evaluation index determination submodule, used to determine a second evaluation index reflecting the frequency change rate;

[0077] A comprehensive evaluation index determination submodule is used to determine the comprehensive evaluation index of the power grid according to the first evaluation index and the second evaluation index.

[0078] The vulnerability assessment module is used to establish a network model of module components based on the model, and to assess the stability of the power grid frequency based on the evaluation indicators defined in the indicator determination module, including:

[0079] The first evaluation submodule is used to evaluate the frequency stability of the power grid by randomly removing a certain proportion of nodes to simulate faults and analyze the impact on frequency stability;

[0080] The second evaluation submodule is used to conduct a secondary evaluation of the grid frequency stability, remove important nodes based on the node characteristic parameters, and further evaluate the frequency vulnerability;

[0081] The early warning system issues early warning information based on the assessment results of the frequency vulnerability assessment system, including:

[0082] An early warning module is used to send early warning information to the user terminal;

[0083] A communication module, used to establish a data connection between the early warning module and the user terminal;

[0084] User terminal, used to receive warning information;

[0085] The safety protection system is used to provide safety protection for the power grid according to the warning information issued by the early warning system. Specifically, it includes: an automatic execution control strategy module, which is used to adjust the load and power generation scheduling of the power grid to maintain the stability of the power grid frequency.

[0086] Embodiment 2, a warning method of a power grid frequency safety warning device comprises the following steps:

[0087] Step 1: Collect real-time data of the power grid, including:

[0088] Use data acquisition systems to obtain real-time grid operation parameters from energy management systems, phasor measurement units, and stability control devices;

[0089] Step 2: Build a model and define indicators, including:

[0090] a. Construct a power grid structure model and use the model building module to build the power grid structure model;

[0091] b. Define frequency stability evaluation indicators, including:

[0092] The first evaluation index, response frequency deviation, is calculated as follows:

[0093]

[0094] Among them, Z1 represents the first evaluation index, N 1 The number of nodes in the power grid after the surface fault occurs,

[0095] N represents the number of nodes in the power grid at the initial moment. The larger the first evaluation index is, the better the power grid operation status is;

[0096] The second evaluation index reflects the frequency change rate, and the calculation formula is:

[0097]

[0098] Among them, Z2 represents the second evaluation index, F l represents the transmission power of line l, D 1 represents the power grid after the fault occurs, S represents the power grid at the initial moment, and the smaller the second evaluation index is, the better the power grid operation status is;

[0099] The comprehensive evaluation index, combined with the first evaluation index and the second evaluation index, is calculated as follows:

[0100] Z=αZ1+βZ2

[0101] Among them, Z represents the comprehensive evaluation index, α and β are weight coefficients, and the larger the comprehensive evaluation index, the better the grid operation status;

[0102] Step 3: Frequency vulnerability assessment, including:

[0103] a. An assessment, including:

[0104] a1. Calculate the initial value of the comprehensive evaluation index of the power grid;

[0105] a2. Randomly remove a certain proportion of nodes, recalculate the comprehensive evaluation index of the power grid, and obtain the relationship between the proportion of removed nodes and the change of the comprehensive evaluation index of the power grid;

[0106] a3. Evaluate the frequency stability of the power grid according to the changes in the comprehensive evaluation indicators of the power grid and obtain an evaluation result;

[0107] b. Secondary evaluation, including:

[0108] b1. Calculate the characteristic parameters of the node:

[0109]

[0110] Among them, S i represents the characteristic parameter of node i, ρ jk represents the number of all shortest paths from node j to node k, ρ jk (i) represents the number of all shortest paths from node j to node k that pass through node i;

[0111] b2. Sort the nodes according to their characteristic parameters from large to small, remove a certain proportion of nodes, and recalculate the comprehensive evaluation index of the power grid;

[0112] b3. Obtain the relationship between the ratio of removed nodes and the change of comprehensive evaluation index of the power grid, evaluate the frequency stability of the power grid according to the change of comprehensive evaluation index of the power grid, and obtain the secondary evaluation result;

[0113] Step 4: Generate and send warning information, including:

[0114] a. The early warning module generates early warning information. When the frequency vulnerability assessment results show potential risks, the early warning module generates early warning information;

[0115] b. The communication module establishes a connection and sends warning information. The communication module establishes a data connection between the warning module and the user terminal;

[0116] c. The user terminal receives and displays the warning information, and the operator responds according to the warning information;

[0117] Step 5: Implement safety protection measures and automatically execute corresponding control strategies based on early warning conditions.

[0118] The parts of the present invention that are not described in detail are prior art. It is obvious to those skilled in the art that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, no matter from which point of view, the above-mentioned embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the present invention, and any figure marks in the claims should not be regarded as limiting the content of the claims involved.

Claims

1. A power grid frequency safety early warning device, characterized in that: include: Data acquisition system, used to collect power grid operation parameters in real time; Frequency vulnerability assessment system, which evaluates the grid frequency stability based on the collected data; The early warning system issues early warning information based on the assessment results of the frequency vulnerability assessment system; The safety protection system is used to provide safety protection for the power grid based on the warning information issued by the early warning system.

2. A power grid frequency safety early warning device according to claim 1, characterized in that: The data acquisition system includes a data acquisition module that obtains real-time data of the power grid from the energy management system, phasor measurement unit and stability control device.

3. A power grid frequency safety early warning device according to claim 1, characterized in that: The frequency vulnerability assessment system includes: A model building module is used to construct a topological network model that reflects the frequency characteristics of the power grid; An index determination module is used to define a series of evaluation indexes reflecting frequency stability; The vulnerability assessment module is used to establish a network model of module components according to the model, and to assess the stability of the power grid frequency based on the evaluation indicators defined by the indicator determination module.

4. A power grid frequency safety early warning device according to claim 3, characterized in that: The model building module represents the power grid structure as a topological network G(U, L), where U={U1, U2, …, UN} is a node set, U represents a substation, and N represents the number of nodes; L={L1, L2, …, LM} is an edge set, L represents a transmission line set, and M represents the number of transmission lines.

5. A power grid frequency safety early warning device according to claim 3, characterized in that: The indicator determination module includes: A first evaluation index determination submodule, used to determine a first evaluation index reflecting a frequency deviation; A second evaluation index determination submodule, used to determine a second evaluation index reflecting the frequency change rate; The comprehensive evaluation index determination submodule is used to determine the comprehensive evaluation index of the power grid according to the first evaluation index and the second evaluation index.

6. A power grid frequency safety early warning device according to claim 3, characterized in that: The vulnerability assessment modules include: The first evaluation submodule is used to evaluate the frequency stability of the power grid by randomly removing a certain proportion of nodes to simulate faults and analyze the impact on frequency stability; The second evaluation submodule is used to conduct a secondary evaluation of the grid frequency stability, remove important nodes based on the node characteristic parameters, and further evaluate the frequency vulnerability.

7. A power grid frequency safety early warning device according to claim 1, characterized in that: The early warning system includes: An early warning module is used to send early warning information to the user terminal; A communication module, used to establish a data connection between the early warning module and the user terminal; User terminal, used to receive warning information.

8. A power grid frequency safety early warning device according to claim 1, characterized in that: The safety protection system includes: The automatic execution control strategy module is used to adjust the load and dispatch the power generation of the power grid to maintain the stability of the power grid frequency.

9. A power grid frequency safety early warning device according to any one of claims 1 to 8, characterized in that: The early warning method of the power grid frequency safety early warning device comprises the following steps: Step 1: Collect real-time data of the power grid, including: Use data acquisition systems to obtain real-time grid operation parameters from energy management systems, phasor measurement units, and stability control devices; Step 2: Build a model and define indicators, including: a. Construct a power grid structure model and use the model building module to build the power grid structure model; b. Define frequency stability evaluation indicators, including: The first evaluation index, response frequency deviation, is calculated as follows: in, represents the first evaluation index, The number of nodes in the power grid after the surface fault occurs, Indicates the number of nodes in the power grid at the initial moment; The second evaluation index reflects the frequency change rate, and the calculation formula is: in, represents the second evaluation index, represents the transmission power of line l, Represents the power grid after a fault occurs. represents the power grid at the initial moment; The comprehensive evaluation index, combined with the first evaluation index and the second evaluation index, is calculated as follows: in, represents the comprehensive evaluation index, and is the weight coefficient; Step 3: Frequency vulnerability assessment, including: a. An assessment, including: a1. Calculate the initial value of the comprehensive evaluation index of the power grid; a2. Randomly remove a certain proportion of nodes, recalculate the comprehensive evaluation index of the power grid, and obtain the relationship between the proportion of removed nodes and the change of the comprehensive evaluation index of the power grid; a3. Evaluate the frequency stability of the power grid according to the changes in the comprehensive evaluation indicators of the power grid and obtain an evaluation result; b. Secondary evaluation, including: b1. Calculate the characteristic parameters of the node: in, Representation Node The characteristic parameters of Represents a slave node To Node The number of all shortest paths, Represents a slave node To Node Among all the shortest paths, the ones passing through the node the number of b2. Sort the nodes according to their characteristic parameters from large to small, remove a certain proportion of nodes, and recalculate the comprehensive evaluation index of the power grid; b3. Obtain the relationship between the ratio of removed nodes and the change of comprehensive evaluation index of the power grid, evaluate the frequency stability of the power grid according to the change of comprehensive evaluation index of the power grid, and obtain the secondary evaluation result; Step 4: Generate and send warning information, including: a. The early warning module generates early warning information. When the frequency vulnerability assessment results show potential risks, the early warning module generates early warning information; b. The communication module establishes a connection and sends warning information. The communication module establishes a data connection between the warning module and the user terminal; c. The user terminal receives and displays the warning information, and the operator responds according to the warning information; Step 5: Implement safety protection measures and automatically execute corresponding control strategies based on early warning conditions.

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