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65 results about "Branch and bound method" patented technology

Power grid optimal planning method of large-scale grid-connected wind farm

The invention discloses a power grid optimal planning method of a large-scale grid-connected wind farm, comprising the following steps of: step 1, obtaining net rack planning data, system operation predication data and wind power planning data; step 2, constructing a calculation model comprising a target function and a constraint condition of the model; step 3, setting calculation parameters; and step 4, inputting the net rack planning data, the system operation predication data and the wind power planning data, which are obtained by the step 1, and three parameters set by the step 3 into the calculation model constructed in the step 2; utilizing optimization algorithms including a Benders decomposition method, a branch and bound method and the like to solve through a computer. According to the method provided by the invention, a 'peak property' of wind power output is considered and the economic rationality of a power grid optimal planning scheme is ensured through allowing a wind power output peak value with a smaller probability; and the method provided by the invention comprehensively considers two aspects on newly-constructed line investment and wind power comprehensive benefits, and simultaneously ensures the line utilization rate and the wind power comprehensive benefits.
Owner:XI AN JIAOTONG UNIV

Method for generating long-term maintenance strategy of electric distribution system in view of ageing properties of element

The invention provides a method for generating a long-term maintenance strategy of an electric distribution system in view of ageing properties of an element. The method comprises the following steps of: step 1, collecting information to form a maintenance basic database for electric distribution; step 2, establishing a long-term maintenance optimizing model of the electric distribution system; and step 3, calling the maintenance basic database formed in the step 1, substituting the maintenance basic database into the long-term maintenance optimizing model of the electric distribution system in the step 2, and solving by using a branch-and-bound method to obtain the long-term maintenance strategy of the electric distribution system in view of the ageing properties of the element. From a view point of the electric distribution system, based on a time-variation ageing model of transformer and breaker equipment, the method provided by the invention can be used as a support of an electric distribution automatic system to effectively establish the long-term maintenance strategy of the electric distribution system by taking a minimum sum of a maintenance cost in a maintenance period and a cost caused by faults as a target function, considering losses to users and electric power companies which are caused when the equipment is stopped in the process of maintaining, and comprehensively considering the influence of the maintenance on the improvement of a failure rate of the equipment and the reliability of the system.
Owner:XI AN JIAOTONG UNIV

AVC (automatic voltage control) system-based reactive voltage optimization method and device

The embodiment of the application discloses an AVC (Automatic Voltage Control) system-based reactive voltage optimization method. The method comprises the following steps of: receiving a CIM (Common Information Model) which is derived through an SCADA (Supervisory Control And Data Acquisition) system; receiving input and switching out status information of reactive-load compensation equipment which is derived through a PI (Plant Information System), and reactive-load measurement section real-time data of transformer substations; on the basis of the CIM, optimally calculating the input and switching out status information of the reactive-load compensation equipment and the reactive-load measurement section real-time data through an optimized reactive voltage algorithm, and generating an optimized strategy, wherein the optimized reactive voltage algorithm comprises a primary dual interior point method, a branch-and-bound method and/or a voltage correcting control model method; and the AVC system controls optimization of the voltage according to the optimized strategy. The embodiment of the application further discloses an AVC system-based reactive voltage optimization device. Utilization efficiency of electrical energy can be improved through the embodiment of the application.
Owner:STATE GRID CORP OF CHINA +2

Method for optimal distribution of time of energy harvesting relay system based on relay selection

The invention aims at a multi-relay system with an energy harvesting function and provides a method for optimal distribution of time of an energy harvesting relay system based on relay selection. In the method, a plurality of relay nodes work under an energy harvesting mode of wireless energy transmission (WET), an optimization model with maximum system end-to-end throughput is constructed based on the limitations of energy causality and data causality, and a branch and bound method is adopted to select the relay node used by each time slot. A simplex method and an independent solution method are respectively adopted to carry out optimal distribution on the transmission time of the source node and the relay node in each time slot for different service conditions of the relay node about the residual energy, so that the data quantity received by the target node is improved. According to the method, pairing of the relay node and the transmission time slot during multi-relay cooperation and optimal distribution of the transmission time of the source node and the relay node are realized, so that the system throughput performance is effectively improved, and the method has an advantage that the energy consumption expenditure is saved.
Owner:NANJING UNIV OF POSTS & TELECOMM

Distribution network regional voltage distributed coordinated control method and system

The invention discloses a distribution network regional voltage distributed coordinated control method and system. The method comprises a step of determining the installation positions of line voltageregulators in a power transmission line when there is no light, a load is maximum and a voltage loss rate is smaller than a set value, a step of dividing the power transmission line into multiple regions by using the installation positions of the line voltage regulators as boundaries, a step of establish a regional optimization model with the minimalization of the active loss of the power transmission line and the total cost of loss of photovoltaic power generation in the regions as an optimization target, a step of performing distributed coordination optimization between the regions by usingan alternating direction multiplier method and determining the optimal objective function of each regional optimization model and the boundary voltage of each region after distributed coordination optimization, and a step of determining the gear positions of the line voltage regulators by using a branch bound method, and regulating the voltage of each region of a distribution network. According to the invention, the problems of the time and space mismatch of a power supply with a high-permeability photovoltaic distribution network and the load and voltage out-of-limit can be solved.
Owner:TIANJIN UNIV +4

Track space-time conflict based integer programming modeling method

ActiveCN107133715AImprove efficiencyOptimize the preparation structureResourcesTime informationProgram planning
The invention discloses a track space-time conflict based integer programming modeling method, which comprises the steps of station route information collection, train selectable route matching, integer programming modeling and model solving and operation process output, wherein in the step of station route information collection, information of tracks required to be passed in order to use each in-route at a conflict-free state, turnout information and occupation time information of each track are collected; in the step of train selectable route matching, a train route matching operation is performed on each train with an operation plan to be compiled, and an in-route pair set is generated; in the step of integer programming modeling, variable and symbol definition, constraint definition and target definition are performed, and a plurality of object lists are generated; and in the step of model solving and operation process output, a model is solved by using a branch and bound method, and the train is compiled. The method disclosed by the invention is high in equipment utilization rate and high in compiling efficiency, and can set different compiling objectives, optimize the compiling structure and avoid conflicts of trains; and the safety on the aspects of time and space is guaranteed.
Owner:成都一石科技有限公司

Resource allocation method based on equivalent capacity in wireless virtual network

The invention discloses a resource allocation method based on equivalent capacity in a wireless virtual network, for solving the problem of resource virtualization and distribution and service flow admission control. The method comprises the following steps: importing an SC-FDMA uplink system to serve as a wireless virtual network system; establishing a finite state Markoff channel model, and obtaining carrier resource statistical information; obtaining equivalent bandwidth information according to different service requests; giving a QOS index sequence to obtain equivalent capacity information; establishing an optimal resource allocation model according to the equivalent bandwidth information and the equivalent capacity information; and resolving the optimal resource allocation model by using a branch and bound method to obtain an optimal equivalent capacity resource allocation scheme. According to the resource allocation method disclosed by the invention, the resource measurement is more accurate and compact, the resource utilization rate is improved, a dynamic pricing mechanism is imported, so that the resource allocation between virtual networks is more balanced and rational, the access rate is high, the delay is shorter, a flexible and varied resource allocation scheme and admission control technology are provided, and a new technical scheme is provided for the implementation of virtual operators.
Owner:XIDIAN UNIV

Multi-mode public transport time table optimizing method for last transfer demand

InactiveCN106845734AReduce transfer failure rateForecastingFailure rateTraffic network
The invention discloses a multi-mode public transport time table optimizing method for last transfer demand. The method comprises the following steps: screening a key transfer relation and an associated site according to passenger flow characteristics; acquiring running information of rail transit and ground public transportation based on a planned time table and historical running data; acquiring a passenger transfer walking time and a number of bus station parking berths through investigation; proposing a time table optimization target and an adjusting strategy, and establishing a night-time time table two-stage optimization model; establishing a time table optimization model for a last train transfer problem of the rail transit at a first stage, and acquiring an optimum adjusting scheme by utilizing a branch and bound method; and at a second stage, based on the rail transit time table generated at the first stage, considering the constraint of the bus station berths number, establishing a bus time table optimization model for the ground public transportation and the rail transit last train transfer problem, and acquiring an optimum adjusting scheme by utilizing a branch and bound method. The method can be used for systematically decreasing a transfer failure rate in a multi-mode public transport network.
Owner:SOUTHEAST UNIV

WAMS-based low-frequency oscillation decentralized controller design method considering interaction

The invention discloses a WAMS-based low-frequency oscillation decentralized controller design method considering interaction which can be applied to low-frequency oscillation control of a power system. The method comprises the steps of: acquiring modal information by integrating multiple identification results; identifying controllability and observability by adopting a state subspace model identification method (N4SID), and determining installation positions of controllers and candidate feedback signals; transferring functional matrix definition according to MIMO for identification and solution row by row, calculating a highly-controllable low-interaction control loop combination by utilizing a branch and bound method, and converting a complex multi-controller coordination design problem into a simple decentralized controller independent design problem; designing a PSS for a region pattern by adopting an identification-based pole placement method, and designing the controllers for an interval pattern by adopting a model prediction control method. The good control effects of the two types of independently designed controllers verify effectiveness of the WAMS-based low-frequency oscillation decentralized controller design method. The WAMS-based low-frequency oscillation decentralized controller design method provides a new idea for designing a multi-damping controller based on identification coordination.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Comprehensive coordination control policy of reactive voltage of power distribution network

The invention relates to a comprehensive coordination control policy of the reactive voltage of a power distribution network, and belongs to the technical field of voltage control of the power distribution network. The coordination control policy is executed by following steps: 1) acquiring parameters of the power distribution network; 2) establishing an equivalent network of the power distribution network; 3) calculating a power grid voltage deviation value of the power distribution network based on the equivalent network in step 2; 4) setting a target function and constraint conditions; 5) solving the target function and the constraint conditions; 6) determining integral solutions of solutions or a solution set in step 5) by employing a branch and bound method; and 7) forming a final combined coordination control scheme according to the integral solutions obtained in step 6), and giving a control command of the transformer gear position and capacitor set switching. According to the method, optimization is realized in consideration of characteristics and communication conditions of regional power distribution network equipment by regarding the minimum global node voltage deviationdegree as the target, and effects of improving the power factor of the power grid and reducing the transmission loss are achieved.
Owner:JIANGSU ELECTRIC POWER CO +2

Optimized operation method of cool and thermal power comprehensive energy system

The invention provides an optimized operation method of a cool and thermal power comprehensive energy system. The optimized operation method comprises the steps of: 1) taking the optimal overall operating economic efficiency of the cool and thermal power comprehensive energy system as the core, considering multi-time scale characteristics of the cool and thermal power comprehensive energy system,and constructing a system operating total cost minimum objective function; 2) establishing an equipment constraint model and a power balance constraint model as the multi-time scale characteristics ofthe cool and thermal power comprehensive energy system are considered, and regarding the equipment constraint model and the power balance constraint model as constraint conditions of the system operating total cost minimum objective function; 3) and adopting a branch and bound method, and solving the system operating total cost minimum objective function according to the constraint conditions instep 2). For the complex structure and operation mechanism of the cool and thermal power comprehensive energy system, the optimized operation method can improve the energy utilization rate, reduces the operating cost, and realizes the optimized operation of the cool and thermal power comprehensive energy system.
Owner:TSINGHUA UNIV

Voltage source converter-comprising alternating current and direct current series-parallel power grid reactive optimization method

The invention discloses a voltage source converter-comprising alternating current and direct current series-parallel power grid reactive optimization method, and belongs to the field of optimization and dispatching of an electric power system. At current, reactive regulation after flexible direct current power transmission is introduced is not taken into consideration in an AVC strategy, and an effective active and reactive closed loop control method for the voltage source converter is absent. The reactive optimization method comprises the steps of establishing a flexible direct current powertransmission system reaction model; establishing a reactive optimization constraint condition of the flexible direct current power transmission system, and a target function, obtaining a reactive optimization model, and solving the reactive optimization model according to the set constraint condition; and specific to the established reactive optimization model, solving the target function by adopting a branch and bound method in combination of a prime-dual interior point method. By virtue of the technical scheme, the flexible direct current convertor station reactive model is established, andthe targeted reactive control method is designed, so that the reactive adjustment capability of the voltage source converter is utilized fully, the voltage control capability in the alternating current and direct current power grid series-parallel condition is improved, and network loss is lowered.
Owner:STATE GRID FUJIAN ELECTRIC POWER CO LTD +1

Three-phase reactive power optimization method of active power distribution network

The invention provides a three-phase reactive power optimization method of an active power distribution network. The three-phase reactive power optimization method comprises the steps of inputting trend data, and constructing a three-phase active power distribution network reactive power optimization model in consideration of an interphase mutual inductance of the branch circuit in a manner that the least value of a power distribution network active network loss is used as an objective function; converting the three-phase active power distribution network reactive power optimization model to a semi-definite programming relaxation model, and solving according to a semi-definite programming method; processing a discrete variable according to a sensitivity analysis method and a branch-and-bound method, and obtaining an iterative value; substituting the iterative value into the semi-definite programming relaxation model, and solving again until an optimization model optimal solution which contains the discrete variable. The three-phase reactive power optimization method of the active power distribution network realizes reactive power optimization calculation of a three-phase active power distribution network and furthermore realizes accurate expression for different-type load conditions in the power distribution network.
Owner:CHINA ELECTRIC POWER RES INST +4

A multi-user computing migration method based on multi-radio communication

The invention belongs to the field of mobile cloud computing, and particularly relates to a multi-user computing migration method based on multi-radio frequency communication. The method comprises thefollowing steps: a controller models the multi-radio frequency multi-user computing migration problem by using a multi-radio frequency multi-user computing migration modeling method based on parameter analysis according to the collected information of all users and the target of the system, and obtains an initial problem model Theta; According to the characteristics of the initial problem model Theta obtained in the previous step, the controller relaxes and transforms the model by using the relaxation and linearization method based on McCormick envelope, and obtains the relaxed problem modelTheta *. The controller uses branch-and-bound method to solve the relaxed problem model Theta obtained in the previous step, which maximizes the total number of beneficiaries and reduces the cost of user migration. The method of the invention simultaneously considers the calculation time delay and the calculation energy problem of the user, can meet the diversity of the user requirements, has highdata transmission rate of the user, and greatly improves the utilization efficiency of the multi-radio frequency.
Owner:HARBIN ENG UNIV
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