39results about How to "Avoid cascading failures" patented technology

The invention provides a power system cascading failure simulation method based on a unified power flow controller and belongs to the technical field of power system security and reliability protection. A computer is used for determining the installation position of the unified power flow controller in a power system firstly, determining an active power flow betweenness threshold value of each node of the power system, performing power system cascading failure simulation based on the unified power flow controller and finally calculating measurement index for reflecting severity of cascading failure through procedures. The power system cascading failure simulation method gives consideration to power flow directivity and the operation mode of the system, optimizes the installation position for installing the unified power flow controller, effectively performs line parameter regulation while meeting safe operation constraints of the power system, and can reflect the propagation process of the cascading failure of the power system actually. The power system cascading failure simulation method based on the unified power flow controller can be widely applied to the cascading failure simulation of the power system, is particularly suitable for the cascading failure simulation of a large-scale complicated power system, and provides a scientific basis for preventing occurrence of the cascading failure of the power system.

The invention discloses an electric power system protection and control method based on a risk assessment. The method comprises the following steps: carrying out the risk assessment on an electric power system, and calculating power network risk values; establishing a protection and control object function; inputting electric power system running states and parameters; and according to the protection and control object function and the power network risk values, formulating electric power system protection and control measures. According to the invention, risk theories are applied to the protection and control of the electric power system, the problem of formulating protection and control measured by reliance on experience of dispatchers is solved, and quantifiable measures can be obtained by use of the method so as to effectively realize safety protection and control of the electric power system. Besides, the method, on the basis of the risk assessment, takes control cost into consideration in an integrated approach, draws up the protection and control object function and formulates the quantifiable protection and control measures according to the object function so as to reduce the control cost as much as possible under the condition that safety protection of the electric power network is realized.

The invention relates to a power system cascading failure analysis model and probability calculation method based on a Markov process. The method comprises the following steps of: differentiating operation characteristics of different components of a power system, and, in combination with state information of the power system, where system components are, analyzing the shutdown probability of the components; considering the correlation between failure events in a cascading failure evolutionary process, describing a cascading failure transfer process through the Markov process, searching a cascading failure event of the system under different initial failure conditions, establishing a cascading failure event model, and generating a power system cascading failure state space in the Markov process; and, analyzing the system transfer probability in a cascading failure state space, and calculating the different-scale cascading failure probability. According to the method disclosed by the invention, while the calculation efficiency is ensured, the cascading failure event of the system under different initial failures is discovered; furthermore, the cascading failure probability is calculated; a corresponding system improvement measure is provided; the cascading failure is prevented; the system risk is reduced; and the power supply capability of the power system is increased.

Embodiments are directed to establishing a model for testing cloud components and to preventing cascading failures in cloud components. In one scenario, a computer system models identified cloud components (including cloud hardware components and/or cloud software components) as health entities. Each health entity is configured to provide state information about the cloud component. The computer system establishes declarative safety conditions which declaratively describe cloud computing conditions that are to be maintained at the identified cloud components. The computer system then tests against the declarative safety conditions to determine which cloud components are or are becoming problematic. Upon determining that an error has occurred, the computer system notifies users of the error and the component at which the error occurred. Guarded interfaces are established to ensure that actions taken to fix the error do not cause further failures.

The invention relates to a method for simulating a power grid interlocking fault based on complicated network theoretical calculation and correction control, and belongs to the technical field of safety and reliability protection of power systems. The method comprises the following steps of utilizing a computer, and performing procedures; firstly, calculating the optimum trend of a power system under the normal condition; calculating the betweenness of each node, determining a betweenness threshold value of each node of the power system, simulating the interlocking fault of the power system, and finally calculating the total loss load of the interlocking fault. The method has the advantages that under the condition of meeting the safety running constraint requirement of the power system, the influence of correction control on the interlocking fault can be simulated by adjusting the output power and reduced load of a power generator, the influence of the change of load distribution on the interlocking fault can be reflected, and the propagation process of the interlocking fault of the power system can be well reflected; the method is widely applied to simulate the interlocking fault of the power system, is particularly suitable for simulating the interlocking fault of large complicated power systems, and can provide scientific basis for preventing the occurrence of the interlocking fault of the power system.

The invention belongs to the field of power system relay protection and power grid cascading failure analysis and discloses a power grid N-k analyzing method based on relay protection system hidden failures. The method comprises the step of analyzing several typical hidden failure models of a relay protection system, the step of establishing solving models of various hidden failure trigger probabilities according to the hidden failure models, the step of carrying out the expected analysis on the power grid N-k according to the timing sequence characteristics of the hidden failure models to obtain the power grid N-k failure path and occurrence probability caused by the protection hidden failures. The method takes multiple types of protection hidden failures into consideration, the power grid N-k failure occurring and expanding process can be analyzed in the aspect of mechanism, the calculating accuracy of the N-k failure probabilities is improved, more N-k failure paths are found, and the limitation of a traditional N-k analysis method is compensated.

The invention relates to a current sensorless grid access current control method applicable to a grid-connected inverter, and relates to a system which consists of a grid-connected inverter main circuit and a grid-connected inverter control circuit; the grid-connected inverter control circuit comprises a grid access current open loop control module and a PWM generation module; the grid access current open loop control module comprises a first proportional regulator, a second proportional regulator, a time-delay device and an summator; the input ends of the first proportional regulator and thesecond proportional regulator are both led out to be used as the grid access current reference signal input end; the output end of the first proportional regulator is connected with the input end of the summator; the output end of the second proportional regulator is connected with the input end of the time-delay device; the output end of the time-delay device is connected with the input end of the summator; and the output end of the summator is connected with the PWM generation module. By virtue of the open loop current control method adopted by the system, non-static-error tracking of the grid access current reference signal by the grid access alternating current can be realized, and the severe operation conditions of power grid harmonic, imbalance and fault can be adapted.

The invention relates to a method for searching key failure nodes in a power heterogeneous communication network system. A self-organized critical theory of a complex network is introduced into the method; furthermore, key network nodes causing conversion of a power heterogeneous communication network from a self-organized state to a critical state can be found by using an iterative method; therefore, a large-area cascading failure of the network can be avoided; and the reliability of the power communication network system is improved. The method comprises the following steps of: judging whether the network satisfies the complexity or not; performing regional division of the large power heterogeneous communication network; searching nodes in the divided regional network so as to find out key failure nodes; rapidly recovering the key failure nodes or making a key failure node cut-off scheme; and searching other triangular divided local network areas.

The invention relates to a power transfer solving method under a grid failure state, aiming at a grid provided with a wide area measurement system (WAMS). An overlay principle is utilized, and the network state in normal operation is overlaid with the state of a single-power failure additional network only under the action of failure power supply so as to obtain network power distribution after a failure circuit is removed and further solve for a power transfer amount on a non-failure circuit. A great deal of simulation test results show that the method can accurately solve for the power transfer amount under the grid failure state and solve the key technical problems that non-convergence easily occurs and solving can not achieved in the traditional tide solving. The power transfer solving method under the grid failure state can effectively solve the power amount transferred to the non-failure circuit after failure occurs to a transmission line, and is still effective even under the condition that network tide can not be converged after the failure.

The invention relates to a ship fire extinguishing system cascading failure evaluation method for distributed intelligence control. The method carries out distributed intelligence control on an existing ship fire extinguishing system on the basis of fuzzy control, builds cascading failure indexes of the ship fire extinguishing system and judges the cascading failure situation. The method includes the steps that a ship cabin is divided into three kinds according to the fire danger degree, information of four parameters undergoes normalization preprocessing, a fire alarm grade evaluation result of the ship cabin is obtained, and a main machine judges the alarm degree of the ship cabin. The method can improve reliability and accuracy of an automatic fire alarm system of the ship cabin, improve the ability to avoid cascading failures and similar extreme disasters, and reduce occurrence of the extreme disasters. According to the method, due to the fact that fire characteristics of the ship cabin are taken into consideration, chain alarm is achieved. Therefore, the method can well facilitate ship environment, improve ship safety and enhance practicality.

The invention relates to a farmland wireless sensor network and a communication method, and belongs to the technical field of wireless sensors. The wireless network comprises a collection node locatedin the center of a communication area and sensor nodes around the collection node; a plurality of layers of annular regions are formed around the collection node; the sensor nodes are distributed ineach annular region; during networking, a first communication channel is established between the sensor node in the innermost annular region and the collection node, and a first communication channelis established between the sensor nodes in other annular regions and at least one sensor node in the adjacent inner annular region; a second communication channel is established between each sensor node and at least one sensor node in the annular region where the sensor node is located; after obtaining the data, each sensor node transmits the data through the first communication channel at a firstset probability and transmits the data through the second channel at a second set probability; if one communication channel fails, data is transmitted through the other communication channel; the first set probability is greater than the second set probability.

The invention discloses an Internet of Things cloud platform for wastewater purification treatment, which comprises a management terminal for monitoring and managing the operation of wastewater treatment equipment and a service terminal for acquiring operation and maintenance states of all sites needing to be served, receiving a maintenance service request of the management terminal and generatinga maintenance order number according to the early warning service number. The management terminal mainly comprises an equipment management module for establishing and storing an electronic file of the wastewater treatment equipment and recording maintenance and repair data of the wastewater treatment equipment, an operation monitoring module for monitoring the operation state and the operation environment of the wastewater treatment equipment and uploading monitoring data to the management terminal in real time, a fault alarm module for setting different fault parameter thresholds for the wastewater treatment equipment, triggering a threshold range, automatically giving an alarm and generating an early warning service number. A converged communication module is arranged between the management terminal and the service terminal. An after-sales maintenance platform which can monitor equipment operation on line, automatically position faults and realize economy, accuracy and high efficiency can be provided.

The invention relates to a short-circuit current suppression device based on a phase-change resistor, the device comprises the phase-change resistor connected in series on a distribution line, the phase-change resistor comprises a phase-change layer and an electrode, and the electrode is connected with a pulse signal, and the device has the advantages that the phase-change resistor is connected in series on the distribution line and comprises the phase-change layer, the phase change layer is easy to realize conversion from a crystalline state to an amorphous state, so that the resistance of the phase change resistor is changed, the current of the distribution line is changed, the short-circuit level of the distribution line can be effectively reduced, the damage of the heat effect and the electrodynamic effect of short-circuit current to distribution equipment is reduced; the requirement on the breaking capacity of a circuit breaker can be reduced, the voltage sag degree caused by a short-circuit fault can be reduced before a fault loop of the circuit breaker is cut off, the power utilization continuity of a sensitive load is improved, and economic loss brought to a user is reduced.