867 results about "Power system security" patented technology

The invention discloses a power grid security situation predicting method based on an improved deep learning model and belongs to the technical field of power system safety. The power grid security situation predicting method includes: performing power grid security situation evaluation through power grid data collection and preprocessing; aiming at the characteristic that indicator data of power grid security situation evaluation are high in relevance and dimension, providing an improved self-coding network method to lower dimension of the indicator data, and utilizing a data sample after dimension reduction and a power grid security situation value corresponding to a next time monitoring point; adopting an improved deep belief network to build a deep learning situation predicting model with multi-input and multi-output for power grid security situation prediction. By the power grid security situation predicting method, speed and accuracy of power grid security situation prediction can be improved effectively.

The present invention discloses a double-layer defense method facing a power system false data injection attack, comprising an upper-layer defense policy and a lower-layer defense policy. In the upper-layer defense policy, based on internal defense means of a power system, methods such as bad data identification, injected power detection, and the like are mainly comprised, and injected false datais preliminarily detected, to generate attack space; and in the lower-layer defense policy, based on redundancy measurement defense means, a configuration position of a measurement apparatus is optimized by using a two-person zero-sum game theory according to an attack range that can be defended by the measurement apparatus, to make the measurement apparatus to implement an optimal defense capability on an attack behavior that is not detected by the upper-layer policy. The double-layer defense method facing a power system false data injection attack is used to assist a defender in establishinga power system security defense counterattack system.

The invention relates to a self-adaptive screening method for an anticipated fault set in power system security and stability on-line assessment, which is suitable for determining the anticipated fault set in the static, transient and dynamic security and stability on-line assessment of the power system. The method adopts the core concept that the fault set required to be recalculated in the security and stability on-line assessment is determined according to the mode of the security and stability margin of all anticipated faults given by the security and stability on-line assessment in the previous round of the power network. The invention takes the power network security and stability margin and the security and stability mode as the quantitative index of the power network security and stability degree, takes the security and stability margin as the index, and screens the anticipated fault subset required to be recalculated from the anticipated fault universal set by combining the security and stability mode and the degree of change of the running state of the power network as the dynamic anticipated fault set which meets the practical demands of the engineering and is changed along with the running state of the power network; the scale of the anticipated fault set used for the security and stability on-line assessment under the current time section can be reduced, and the computing speed for the security and stability on-line assessment is increased.

The invention relates to a risk perception and early warning method and a system for cascading failures of a wind power base. The method provided by the invention comprises the steps of acquiring real-time operation mode data of a power grid and a wind power plant through SCADA (supervisory control and data acquisition) and a WAMS (wide area measurement system), acquiring possible wind power disturbance of the current power grid by combining with historical data of the wind power plant so as to establish a reasonable failure set, establishing a wind power generating unit dynamic model and a fan safety protection model, simulating dynamic operating conditions of the wind power plant after the power grid breaks down, carrying out power grid transient stabilization analysis after the wind power base breaks down and carrying out static safety analysis after a failure is removed, carrying out calculation and evaluation on the safety stabilization condition of the current power grid after occurrence of the wind power disturbance through a series of indexes which are applicable to early warning for the cascading failures of large wind power bases, analyzing the risk of the occurrence of cascading failures of the large wind power base, and realizing online safety early warning for an electric power system after the wind disturbance. The method and the system provided by the invention are easy to implement, and can visually reflect safe and stable operation conditions of the electric power system including the large wind power base.

The invention discloses a method for the calculating ice coating thickness of a transmission line by utilizing video image processing technique, belonging to the technical field of digital video image processing or online monitoring of the transmission line. The method takes digital image intercepted from a video flowing of the transmission line which is transmitted into a surveillance center as the object of study and processes the image by methods of gradation of image, two-dimension image segmentation, filtration, regional mark and the like in advance. In the process of pretreatment, the image is segmented by adopting a new two-dimension varimax based on simulated annealing genetic algorithm, and the image of the transmission line is marked by adopting eight connected region marking method. Finally, by the contrast and calculation of the pixels of the images which are obtained before and after the ice coating of all the transmission leads, an average value is obtained, and the ice coating thickness is further calculated. When the ice coating thickness of any of the transmission leads exceeds the prescriptive safety range, alarm is given, so that deicing measure is adopted in time, thus providing security for the safe running of an electric power system.

The invention discloses a comprehensive diagnosis method of an oil-immersed transformer based on a fault tree, which includes steps: (1) collecting correlated condition characteristic parameter values of gas dissolved in oil, moisture in oil, local discharge, iron core grounding current, top oil temperature and winding optical fiber temperature measurement of the transformer in real time, (2) normalizing by aid of diagnosed fault types of gas dissolved in oil, (3) counting fault diagnose accuracy of all diagnose methods, (4) obtaining state quantity of measured gas dissolved in oil for respective diagnose, (5) obtaining a fault confidence digit group, and (6) integrating to obtain a fault diagnose result of the transformer. The comprehensive diagnosis method combines advantages of various oil chromatographic diagnose methods, overcomes defects of a single diagnose method, adopts gas dissolved in oil as a diagnose core, is supplemented by fault tree diagnose, masters operation health conditions of the transformer macroscopically, can achieve fault positioning of devices, and has important practical meaning for finding potential hidden fault danger of devices and ensuring safe and stable operation of an electrical power system.

The invention discloses a circuit cluster-based method for analyzing a grid cascading failure, belonging to the technical field of safety protection of a power system. The method comprises the following steps of: applying a Bayes network failure tree theory to cascading failure analysis based on a distribution failure probability model of a self-critical circuit cluster and establishing a probability analysis model for a grid cascading failure based on cascading failure probability analysis of the self-critical circuit cluster in combination with the probability characteristic of a cascading failure developing stage; and through simulating a cascading failure process, performing risk assessment on the cascading failure by using a system load loss index and analyzing weak links of a system. By adopting the method, foundations are provided for a prevention strategy for further research on the reduction of cascading failure risk.

The invention discloses a method for defending false-data injection attacks in the direct-current state estimation of an electrical power system, which belongs to the technical fields of electrical-power system safety and control and comprises the following steps of: estimating the real-time state of a direct-current system by a weighted least square method, and filtering measuring noise and random disturbance; processing a state-estimating result by a maximum standard residual-error detecting method, and detecting and identifying bad data in quantity measurement; and calculating the sensor quantity-measuring combination which is most easily destroyed by the false-data injection attacks by a heuristic algorithm, carrying out encryption protection for a group of sensors, and blocking the false-data injection attacks from occurring from a source. The method can be used for accurately and rapidly defending the false-data injection attacks in the state estimation of the electrical power system, and the state-estimating accuracy and safety of the electrical power system are improved.

The invention provides an electricity market simulating system by adopting an SOA technology, which realizes global simulation for current electricity market of the country, provides technical support means for simulating electricity market operation and electricity system operation in different environmental conditions and market behaviors, globally evaluating market status, preventing market risks, verifying market rules, studying safe and stable operation strategy and measures of the electricity system under electricity market condition, and training electricity market related working staff, and provides a reliable technical analysis tool for high-efficiency excellent operation of the electricity market of the country.

The present invention discloses a power system safety operation intelligent monitoring device and a monitoring method thereof. A camera shooting unit, a radio frequency identification unit, a standardization operation base and an expert base module which are respectively connected with a data processing and analysis software are integrated in a palmtop computer or a portable computer. The information which is processed by the data processing analysis software is respectively connected with a voice prompt and short message alarming module and a wireless data transmitting unit. The wireless data transmitting unit is connected with the monitoring host of a remote data processing center. The device of the present invention is of reasonable structure and good generality and can assist the operator to finish the operation of various devices and the monitoring work of operation trustily. The present invention can connect the device with the other hosts through a wireless interface. The present invention can be widely used in power plants, transformer substations, maintenance and operation groups and other industry fields.

The invention provides a simulation verification method for low voltage ride through (LVRT) of a wind farm. The method comprises the following steps of: analyzing operating characteristics of a wind generation set according to a verified wind generation set electric simulation model; establishing a wind farm electric simulation model, and verifying whether the wind farm has LVRT or not; and establishing a regional power system simulation model comprising the wind farm electric simulation model, and verifying influence of wind farm grid connection on secure and stable operation of a power system. The invention provides a complete and effective method for verifying the LVRT of the wind farm; and the method has positive significance on judging whether the wind farm meets the grid connection requirement or not, avoiding large-scale wind power off-line accidents and ensuring secure and stable operation of a power grid, and lays a foundation for establishing and perfecting a wind power grid-connected authentication system in China.

The invention provides a power system reactive power optimization method based on depth determination strategy gradient reinforcement learning. A deterministic depth gradient strategy algorithm is applied to the traditional power system reactive power optimization problem. The voltage state of the power system is sensed through a depth neural network, a corresponding action decision is then made by using a reinforcement learning method, a correct generator terminal voltage adjustment action, a node capacitor bank switching action and a transformer tapping point adjustment action are made to adjust reactive power distribution in the power system, the active power network loss of the power system is minimized. As the neural network is divided into an online network and a target network, association between parameter updating and adjacent training in each training process of the neural network is avoided, and the problem that reactive power optimization of the power system is caught in local optimization is avoided. On the premise of conforming to the security constraint of the power system, the economical efficiency of the operation of the power system is improved by reducing the network loss of the power system.

The invention discloses a method for conducting power system fault diagnosis by combining information theory with expert system, belonging to the technical field of power system safety treatment. Themethod includes the following steps: firstly establishing a fault diagnosis information transfer model of an actual channel, determining all possible pieces of equipment with fault through forward reasoning of the expert system according to a power cut area where the power system fails, then respectively assuming suspicious equipment, and reasoning out the corresponding action state of switching and protection reversely to obtain all possible information sources in actual communication. Finally, a control center obtains a group of data sequences consisting of the action state of switching andprotection, establishes the fault diagnosis information transfer model based on the actual channel and implements examination, repair and removal of faults according to the fault diagnosis informationtransfer model.

The invention discloses a receiving-end power grid dynamic reactive power compensation equipment configuration position selecting method. Receiving-end power grid dynamic reactive power compensation equipment configuration position selection is based on an electric system safety and stability and dynamic voltage support quantitative analysis method and reflects a combined influence of configuration positions to a system according to a system voltage stability margin and a support effect. The method overcomes the influence that a static configuration method cannot reflect system disturbance, comprehensively and fully reflects an improving effect of dynamic reactive power compensation equipment configuration stations to system safety and stability characters, and sufficiently plays dynamic reactive power compensation equipment roles, and therefore, the receiving-end power grid dynamic reactive power compensation equipment configuration position selecting method has a good actual guiding significance.

The invention discloses a parallel computation method for Newton power flow of a large-scale electric power system, which belongs to the technical field of safe analysis and computation of electric power systems. A modified equation set of the Newton power flow is resolved by using a computer according to a parallel cluster through a program in combination with parallelization technology for updating a Jacobian matrix by a generalized minimal residual method combined with a quasi-diagonal parallel preconditioner so as to realize parallelization of a power flow resolving process of the large-scale electric power system. The method does not need network partitioning in any form and has simple computation and high generality; a forward/backward sweeping dependency relationship does not exist inside an algorithm, and parallel efficiency and computation speed are high; and computation can be performed by the common parallel computer and the parallel cluster and the method is convenient to popularize and apply, and the like. The method can be applied to the parallel power flow computation of the electric power system and is particularly suitable for the parallel computation of the Newton power flow of a large-scale complex electric power system.

The invention discloses a STATCOM (static synchronous compensator) control system adopting a droop control strategy and a control method thereof. The STATCOM control system adopting the droop control strategy comprises a direct-current side capacitor, a three-phase inverter bridge and an inductance-capacitance filter, wherein the direct-current side capacitor and the three-phase inverter bridge are connected in parallel and then connected with the inductance-capacitance filter, and the inductance-capacitance filter is connected to a PCC (Point of Common Coupling) of a power grid by a three-phase switch K through a coupling transformer T. The control method disclosed by the invention comprises the steps of real-time signal collection, computation of active power reference value P*, computation of reactive power reference value Q*, computation of frequency reference value omega* and voltage modulation amplitude reference value E*, computation of phase reference value Delta* and computation of voltage modulation signals; and only one PI (proportional integral) regulator and two droop control coefficients need to be regulated, thus the whole control method is easy to realize, and further the power system can better supply power to users safely, excellently and economically.

The invention discloses an electrical power system key node identification method based on active power load flow betweenness, and belongs to the field of electrical power system safe reliability protection. According to the method, a computer is utilized, the load flow distribution of an electric power system, power in each transmission path and the active power load flow betweenness of each node are confirmed through a program, and finally a key node is identified. The method can take the directivity of load flow and a system operation mode into account simultaneously and can indirectly reflect the influence of voltage and reactive power on an identification result, an identification process corresponds to the actual operation condition of the electric power system better, and can accurately reflect the function of each node in the active power transmission of an electrical power system, and accordingly the key node of the electric power system can be identified effectively. The method can be widely applied to the identification of the key node of the electric power system, is especially suitable for the identification of the key node of a large and complex electric power system, and provides reliable scientific bases for prevention of the accidents of the electric power system.

The invention belongs to the technical field of electrical power system security and stability control and is suitable for a transient security and stability emergency control system to automatically select an on-line strategy or an off-line strategy. On the basis of a transient security and stability quantitative analysis method, the invention provides the index of influence of running state change on transient security and stability for judging the adaptability of the on-line control strategy to the running state change. The invention comprises the following two parts: (1) issuance of the on-line strategy and confirmation of the effectiveness thereof, i.e. checking the security of the on-line strategy to judge whether issuing the on-line strategy to a control device, and judging the effectiveness of the issued on-line strategy constantly; and (2) selection of the on-line strategy and the off-line strategy during failure, i.e. selecting the on-line strategy when 'form characters' detected by the control device are as same as 'form characters' of the on-line strategy, the time for generating the on-line strategy is not long, and the influence degree of the running state change calculated on the basis of measured data of the control device on the transient security and stability meets the requirement; and otherwise, selecting the off-line strategy.

The invention belongs to the technical field of the calculation and analysis of a power system, and discloses a method for comprehensively evaluating the precision of stability calculation models and parameters based on PMU data. The method comprises the following steps: performing time-domain simulation on an electromechanical transient process and an electromechanical dynamic process for the disturbance of a power grid, and adopting a power system security and stability quantitative analyzing method to calculate transient security and stability margins, modes, dynamic oscillation damping ratio and frequency; (2) adopting PMU actually-measured data on the power angle and frequency of a generator and the voltage and frequency of a busbar after the disturbance of the power grid to take place of time-domain simulation results of corresponding physical quantities, and then adopting the power system security and stability quantitative analyzing method to calculate the transient security and stability margins, the modes, the dynamic oscillation damping ratio and the frequency; and (3) comprehensively evaluating the precision of transient and dynamic security and stability calculation models and the parameters by comparing differences between the two transient and dynamic security and stability margins and the modes. Through the method, reliability evaluation on the transient and dynamic security and stability simulation calculation results of the power system is realized.

The invention relates to an on-line detection method for ceramic zero resistance insulators on an alternating current transmission line based on infrared thermal imaging, and belongs to the field of power transmission. The invention aims to provide an on-line detection method for ceramic zero resistance insulators with safety, economy, high efficiency and high accuracy. The invention adopts the technical proposal that when a ceramic insulator string has a zero resistance insulator, the spread voltage of other insulators is boosted, the reactance of the whole insulator string is reduced, the leakage current of the insulator string is increased, and the heating difference of the good insulators and the zero resistance insulators is increased. By shooting thermal field images of the insulator string through a high-precision infrared imaging instrument, adopting image processing technology to extract axial temperature distribution curves of the insulator string, and utilizing the difference of the axial temperature distribution curves of the adjacent insulators, the method achieves accurate judgment of the state of the insulators. The method can be used for zero resistance detection for the ceramic insulators on the alternating current transmission line in grade of 110KV and above voltage, and is applied to lightening workload of detection greatly and improving secure operation level of a power system.

The invention discloses a smart power grid embedded device network detection assessment system which comprises a special network safety detection device, a shadow machine and a power system safety monitoring center. The special network safety detection device analyzes and filters various kinds of network data packs; the shadow machine detects the network state and changes of a host state of the embedded system when the embedded system is under network attack and sends the network state and host station information to the power system safety monitoring center; the power system safety monitoring center obtains a safety detection result by means of multi-dimensional property comprehensive measurement based on platform configuration property measurement, platform operation property measurement and user authentication property measurement. On the premise that normal work of the embedded system is not influenced, real-time and dynamic safety detection and assessment can be carried out on known or unknown power system network attacks quickly and accurately by means of the shadow machine.

The invention provides an intelligent sequential control system and method based on transformer substation internal panoramic data. The intelligent sequential control system is composed of three modules, which are a sequential control state generation module, a sequential control operation order generation module, and a sequential control operation order rehearsal and execution module respectively. The sequential control state generation module analyzes the transformer substation internal panoramic data to divide a running state of a transformer substation into a plurality of interval sequential control states by taking an interval as a unit. The sequential control operation order generation module acquires a sequential control state definition generated by the sequential control state generation module, and assists an operator to generate a sequential control operation order of a substation internal running state switching process. The sequential control operation order rehearsal andexecution module carries out simulated rehearsal and execution of a sequential control operation order process on the sequential control operation order to finish the substation internal running stateswitching process. Based on the intelligent sequential control system and method, the workload of the operator is reduced, the working difficulty of the operator is reduced, and an important significance is achieved for improving the operation efficiency in a transformer substation and guaranteeing the safe and reliable operation of an electric power system.

The invention discloses an intelligent power grid false data injection attack detection method which combines a variational mode decomposition technology and a machine learning technology. The detection method is added behind a power system state estimation part, and comprises the following steps: firstly, decomposing a system state time sequence into a set of a plurality of sub-sequences with different center frequencies by using a variational mode decomposition technology; secondly, in order to compress redundant data to facilitate model training, expressing data segment characteristics by using characteristic quantities based on statistical indexes; and finally, constructing a false data injection attack detector under the smart power grid by taking the calculated feature set as a training set of an online sequential extreme learning machine. In the process, the credible authenticated data can be used as an extended training set to continuously optimize the performance of the detector with the online learning capability. The invention aims to establish an efficient and accurate false data injection attack detection method for the smart power grid to ensure safe control and stable operation of a power system.

The invention discloses a novel power quality control system with a fault current-limiting function and a control method thereof. The novel power quality control system with the fault current-limiting function comprises a three-phase H-leg PWM rectifier, a three-phase four-leg series converter, a thyristor controlled short-circuit branch, a thyristor controlled bypass reactance branch and a corresponding control method. The PWM rectifier and the three-phase four-leg series converter share one direct current side to achieve bidirectional energy conversion, the series converter compensates the fall, the raising and three-phase imbalance of the grid voltage and solves the quality problem of the harmonic voltage, at the same time, the system controls the series converter, the thyristor controlled short-circuit branch and the thyristor controlled bypass reactance branch to limit the current when various short-circuit faults occur on the grid, and thus the purposes of stabilizing the loaded supply voltage, improving power supply quality, protecting the grid and load equipment when short-circuit faults occur and improving the safety and stability of the electric power system are achieved.

The invention discloses a system for optimization, integration and intelligent analysis of operating data of a converting station. According to actual operation situations of an electrical power system, the system for the optimization, integration and intelligent analysis of the operating data of the converting station provides early warning and monitoring information, conducts weighting and quantization after intelligent analysis, optimization and integration, builds a safety and reliability evaluation system of the electrical power system, and ensures that the electrical power system can operate safely and reliably. On the one hand, the system for the optimization, integration and intelligent analysis of the operating data of the converting station can provide a set of scientific quantitative index for monitoring of power operation, and avoids limitations mainly based on experience-based judgments in the past. On the other hand, the system for the optimization, integration and intelligent analysis of the operating data of the converting station enables the specialized persons of supervision organization to be free from vast information analyses and calculations and to directly enter decision-making operations, improves supervision work efficiency, achieves multi-major comprehensive state-sensing of grid operation monitoring and integration of steady states, unstable states and transient states of power grids, improves the effectiveness of the analysis of the power grids, achieves supporting of multi-major comprehensive intelligentization analysis and decision, provides uniform procedures and forms for power grid operation management, and improves overall efficiency of the power grid operation monitoring and controlling and operation management.

The invention relates to a combined static safety analysis method for an electrical-gas coupling multiple energy flow system, belongs to the technical field of operation and control in multiple energy source modes. The method breaks through limit of safety analysis of an electrical power system only taking consideration of the electrical power system itself, the method takes consideration of mutual influence of electrical power supply and gas supply and realizes combined static safety analysis on the electrical-gas coupling multiple energy flow system, so influence of possible preconceived accidents in electrical power supply and gas supply on the two systems are all analyzed, compared with a method carrying out independent safety analysis on electrical power supply and on gas supply, safety analysis precision is improved, and error and determination missing are reduced. The method can be applied to online operation of the electrical-gas coupling multiple energy flow system and works for electrical-gas coupling multiple energy flow energy management, a safety warning is provided when the system has a safety problem or a latent risk, and improvement of operation safety of the electrical-gas coupling multiple energy flow system is facilitated.