289 results about "Reserve capacity" patented technology

A streaming media caching mechanism and cache manager efficiently establish and maintain the contents of a streaming media cache for use in serving streaming media requests from cache rather than from an original data source when appropriate. The cost of caching is incurred only when the benefits of caching are likely to be experienced. The caching mechanism and cache manager evaluate the request count for each requested URL to determine whether the URL represents a cache candidate, and further analyze the URL request rate to determine whether the content associated with the URL will be cached. In an embodiment, the streaming media cache is maintained with a predetermined amount of reserve capacity rather than being filled to capacity whenever possible.

A method of providing restoration routes for protecting traffic in a mesh network is described. The method comprises the steps of generating a set of eligible restoration routes for each span in the network, establishing a bi-criteria objective function in terms of route length and capacity cost for selecting a set of restoration routes, and selecting a set of restoration routes for each span from the eligible restoration routes in dependence upon the bi-criteria objective function. Embodiments of the invention may be useful for shortening the lengths, in terms of hops, of existing restoration routes in a mesh-restorable network and in some cases with negligible spare capacity penalty.

In order to restore a network after a failure, it is important to have sufficient spare capacity available. To ensure restorability, a Hamiltonian mesh, being a closed sequence of links traversing each network node exactly once, is determined and half of its capacity is reserved for restoration purpose. In the case of a line failure of a link other than the links of the Hamiltonian mesh, affected traffic is split in two portions and rerouted over the two directions of the Hamiltonian mesh. In the case the network has no Hamiltonian mesh, a mesh coverage is determined and sufficient spare capacity reserved for restoration purpose.

The invention discloses an optimizing method of an independent microgrid system which comprises diesel generators, a wind driven generator, a photovoltaic array and an energy storage battery. The optimizing method specifically comprises the steps of: considering a coordination control strategy among a combined starting mode of multiple diesel generators, the energy storage battery and the diesel generators on an optimizing plan designing model by an independent microgrid system-based multi-target optimizing design model to ensure that the utilization rate of renewable energy resources in the independent microgrid system is higher and the independent microgrid system is more economic and more environment-friendly in operation; aiming at the stability of the optimizing plant designing model of the system, considering the standby capacity of the stability demand of the independent microgrid system; and carrying out multi-target problem solving by adopting an NSGA-II (Nondominated Sorting Genetic Algorithm II)-based multi-target genetic algorithm on the basis of a solving algorithm of the optimizing plant design model so as to realize multi-target optimization of economy, reliability and environment friendliness of the independent microgrid system.

An expander formulation used in battery paste compositions. The expander formulation incorporates effective amounts, or elevated concentrations of up to 6% of graphite and mixtures of carbon black and graphite to lessen or minimize the accumulation of lead sulfate on the surface of the negative plate during high rate PSOC battery operation, and/or to increase the electrochemical efficiency, the reserve capacity, the cold cranking performance and the cycle life of lead-acid batteries.

Communication traffic policing apparatus and methods are disclosed. Communication traffic restrictions for each communication link in a group of communication links are enforced by allowing transfer of communication traffic associated with respective communication links of the group at transfer rates up to respective per-link transfer rates. In a group enforcement stage, transfer of additional communication traffic associated with a communication link of the group, above the per-link transfer rate for the communication link, is allowed where a combined transfer rate of communication traffic associated with another communication link of the group and the additional communication traffic would not exceed the per-link transfer rate for the other communication link. Thus, one or more individual communication links of a group may be allowed to effectively exceed their per-link transfer rates if one or more other communication links of the group have sufficient spare capacity.

The invention provides an electric vehicle charging station load prediction method based on a support vector machine. The electric vehicle charging station load prediction method based on the support vector machine comprises the following steps of: collecting charging station load before a prediction day and historical data of factors which affect the charging station load; constructing a training sample set according to the historical data; training by the training sample set to obtain the Lagrange multiplier of a support vector machine regression function; according to the Lagrange multiplier, establishing a support vector machine prediction model; and substituting the prediction sample set into the support vector machine prediction model to obtain a charging station load prediction value. According to the electric vehicle charging station load prediction method based on the support vector machine, which is disclosed by the invention, the electric vehicle charging station load prediction precision can be effectively improved, and a more reliable basis is provided for an electric power dispatching department to regulate a dispatching plan, regulate system reserve capacity and optimize the generator set capacity.

The invention discloses a computational fluid mechanics-based cerebrovascular reserve capacity simulation system and method. The system comprises an image data collection module used for obtaining a computed tomography image of a brain blood vessel of a human body, a blood vessel three-dimensional reconstruction module for performing three-dimensional reconstruction on the computed tomography image, a boundary condition extraction module for performing post-processing on the computed tomography image of the brain blood vessel to obtain boundary information required for simulation, a CFD preprocessing module for performing preprocessing required for numerical simulation on a three-dimensional geometric model of the brain blood vessel, a CFD computing module for performing solving on hemodynamics information of all parts of the three-dimensional geometric model of the brain blood vessel, and a CFD post-processing module for comparing a simulation result with a result measured by the boundary condition extraction module. Hemodynamic feature parameters are adopted as standards for evaluating cerebrovascular reserve capacity, so that the one-sidedness of judgment through a geometric structure of the brain blood vessel is avoided, and noninvasive, quantitative and personalized cerebrovascular reserve capacity evaluation can be realized.

The invention discloses a primary frequency modulation control method and system for a photovoltaic power station based on multi-master station coordination control. The method comprises the steps that the active power of the grid-connected point of the photovoltaic power station is collected in real time; since AGC load shedding control reserves power reserve capacity for the photovoltaic power station, the active power of the grid-connected point of the photovoltaic power station is active power Pref when the photovoltaic power station has the load shedding level described in the description; when the grid frequency exceeds the artificial dead zone DB disturbance of primary frequency modulation, a PFC control system calculates the active power variation delta P after frequency fluctuation, and the target value Pset=Pref+ delta P is given to the active power issued to an inverter group; and the active power of the photovoltaic power station is changed to achieve primary frequency modulation. The scheme simply needs to upgrade the algorithm of the control software of a conventional photovoltaic power station inverter, and adds a PFC master station coordination mechanism based on the existing AGC function of the power station, so as to realize multi-master station coordination control of AGC and PFC. Cost can be maximized. The primary frequency modulation function of the photovoltaic power station is used to speed up the frequency recovery of a grid.

A hydroelectric power plant uses a plurality of windmills connected to compressed air generators to produce pressurized air. Pressurized air is used to drive water through a turbine to produce electrical power. The water is recycled and the power plant includes reserve pressurized air tanks to allow the plant to continue to operate when the wind levels are not sufficient to produce high pressure air. The power plant is designed to be operated on a continuous basis based on wind power. When the wind subsides and the reserve capacity has been exhausted, electricity can be drawn from the local utility supplier. When excess power is generated by the power plant, electricity from the power plant can be added to the grid of the local electricity supplier.

The invention discloses a large-scale wind electricity and high energy-carrying load coordination control method. The large-scale wind electricity and high energy-carrying load coordination control method comprises the steps of defining the output of a wind power plant as a negative load according to the output short-term prediction curve and a load prediction curve of the wind power plant, overlaying an original load with the negative load and forming an equivalent load curve; according to the equivalent load curve, on the basis of considering the operation conditions of a wind power generating unit and a thermal power generating unit and the constraint conditions of the units, making generation plans of the wind power generating unit and the thermal power generating unit; according to the generation plan and the rated capacity of the thermal power generating unit, determining the spare capacity of the thermal power generating unit, adopting part of the spare capacity as the wind power pitch peak, and using another part of the spare capacity as the margin of the spare capacity; and when the wind power fluctuates, according to the spare capacity, used as the wind power pitch peak, of the thermal power generating unit, inhibiting the fluctuation of the wind power by adjusting the output power of the thermal power generating unit. The large-scale wind electricity and high energy-carrying load coordination control method has the advantages of being capable of achieving high output, large in application range and good in stability.

A hydroelectric power plant uses a plurality of windmills connected to compressed air generators to produce pressurized air. Pressurized air is used to drive water through a turbine to produce electrical power. The water is recycled and the power plant includes reserve pressurized air tanks to allow the plant to continue to operate when the wind levels are not sufficient to produce high pressure air. The power plant is designed to be operated on a continuous basis based on wind power. When the wind subsides and the reserve capacity has been exhausted, electricity can be drawn from the local utility supplier. When excess power is generated by the power plant, electricity from the power plant can be added to the grid of the local electricity supplier.

A method of capacity reservation. The inventive method first obtains historical customer delivery data, classifies the customers into different category levels according to the delivery data, and reserves capacity for the customer categories accordingly.

The invention discloses a standby volume analytical method under a coordinating dispatch mode of batch-type energy and conventional energy. The method comprises the following five steps of calculating a standby past sample data region, obtaining similar cluster time intervals in a planed date, carrying out statics on a forecast output power deviation distribution of each time interval, obtaining a probability density function of the standby volume of wind energy, and calculating a rotation standby volume of a system under the coordinating dispatch mode of the batch-type energy and the conventional energy. With the adoption of the analytical method, according to a consideration of the coordinating dispatch of assembling units of the batch-type energy and the conventional energy, statics and analysis on data of past wind-power operation are carried out to form the current requirement on the rotation standby volume, safety guarantee is provided for the coordinating dispatch of the batch-type energy and the conventional energy, a reasonable standby volume is provided, and the realization of economical requirement on operation of a power system is facilitated. The method has the characteristics of low calculation intensity and strong adaptability, and is more suitable for popularization and application of connecting with dispatch mechanisms with larger power of wind power.

The invention provides a wind power consumption ability analysis method considering the standby requirement. The method includes the following steps that a standby requirement probability distribution model is established after wind power integration is conducted; standby constraint conditions are determined; a production simulation model considering the standby requirement is established; according to the generated simulation model, the wind power consumption ability is analyzed. According to the method, the standby requirement probability distribution model is established after wind power integration is conducted, the optimal required reserve capacity is obtained after wind power integration is conducted so that a start-up mode and a service capacity plan curve of a unit can be optimized, the wind power consumption ability can be improved, and a reference is provided for regional power grid planning.

The invention relates to a grid multi-time-scale dispatching method comprises steps of successively performing a day-ahead dispatching model, an intraday dispatching model and a real-time dispatchingmodel, which all uses a conventional unit, wind power, a CAES power station and a flexible load as dispatching resources and use operating economy as an optimization objective, in order to obtain theoutput plans of the conventional unit, wind power and the CAES power station, a flexible load dispatching plan, a rotary reserve capacity, and an AGC capacity acquisition plan, wherein the constraintsof each dispatching model include the operational constraints of each dispatching resource, and the constraints of the real-time dispatching model also include the constraints that the CAES power station participates in the grid AGC frequency modulation. The method takes a system including the CAES power station and the flexible load as a research object, comprehensively considers the dispatchingcharacteristics of the CAES power station and the multi-type flexible load which reduce the system air abandonment amount at different time scales, additionally considers the AGC unit rotary reserveand the auxiliary frequency modulation service of the CAES power station, effectively improves the level of wind power consumption and ensures efficient and safe economic operation of the system.

The invention provides an optimized dispatching method for a power grid including pumped storage units. The method includes the following steps: step 1, aiming at minimizing the operating costs of allunits, establishing an objective function model; step 2, setting various types of constraint conditions according to the daily actual working conditions of a power grid system including the pumped storage units; step 3, obtaining a mixed integer nonlinear programming model for power grid optimized dispatching according to the objective function model and the various types of constraint conditions, and performing linearization on the nonlinear part of the model to obtain a mixed integer linear programming model for power grid optimized dispatching; and step 4, calling a mathematical optimization toolbox CPLEX solver to solve the mixed integer linear programming model. The dispatching method considers the start-stop costs of each unit and the rotational reserve capacity constraints that canbe provided by the pumped storage units under different operation conditions, also performs linearization on an expression to convert the model into the mixed integer linear programming model, can carry out fast and reliable solution by using a mature solver, and has a good engineering practical value.

The invention discloses a virtual power plant day-ahead optimal scheduling system and method considering wind power uncertainty. The method comprises the steps: obtaining the next-day wind power fulloutput prediction of a virtual power plant and the next-day thermal load demand prediction of a borne region, formulating a next-day power generation plan, and reporting the next-day power generationplan to a power grid to obtain a next-day output task of the virtual power plant; establishing a virtual power plant energy supply balance model; determining a virtual power plant spinning reserve capacity of the heat reserve; performing wind power uncertainty processing on the virtual power plant power supply balance constraint to reduce the influence of wind power uncertainty on a day-ahead scheduling plan; establishing an objective function with the maximum daily income of the virtual power plant as an objective, setting constraints and enabling the spinning reserve capacity of the virtualpower plant to meet the wind power fluctuation requirement and all components of the virtual power plant to operate in a safe range; and solving the model by using a particle swarm algorithm to obtaina next-day operation scheduling plan and earnings of the virtual power plant. The external thermoelectric coupling relation of the virtual power plant is reduced, the adjustable range of the power output of the virtual power plant is expanded, and the reserve capacity of the power grid is released.

The invention discloses a robust scheduling method with consideration of flexible adjustment of a power grid structure. The method comprises: (1), a robust scheduling calculation parameter is inputted; (2), a robust scheduling model with consideration of flexible adjustment of a power grid structure is constructed, wherein the model based on a background of dealing with uncertainty uses the pursuit of optimal grid operation economy as an objective function and a related constraint of a decision variable and an operating range constraint under zone uncertainty are met; (3), on the basis of a principle of duality and a Benders algorithm, robust scheduling model solving is carried out; and (4), a robust scheduling result is outputted, wherein the result includes a provided power scheduling output, a reserve capacity, and a power transmission element operating state of a decision. Therefore, uncertainty of the load and renewable energy source power in the power system can be dealt with; a technical support is provided for power system optimization operation under the uncertainty background; and the power system source-load balancing capability as well as security and economy of grid operation is improved.

The invention discloses a congestion dispatch bilevel programming method of considering a real-time operation risk. The method comprises the following steps of building an objective function of an upper model by employing the minimum comprehensive cost of congestion dispatch as the target, carrying out constraining by using constraint conditions of the upper model, and building an objective function of a lower model by employing the minimum operation risk cost as the target and carrying out constraining by using the constraint conditions of the lower model, thereby obtaining a congestion dispatch bilevel programming model; and converting the congestion dispatch bilevel programming model into a mixed-integer linear programming model by using a KKT optimality condition and a linearization method and solving the mixed-integer linear programming model by using a CPLEX to generate an optimal scheme for congestion dispatch. According to the congestion dispatch bilevel programming method, theoperation risk, caused by uncertainty wind power output, to a system can be quantified, power adjustment of the congestion dispatch and joint optimization of the rotating reserve capacity are achieved, the condition of unavailable rotating reserve capacity of the system can be reduced, and resource allocation is further optimized.