83 results about "Loading margin" patented technology

The invention provides an apparatus and method for detecting a driver status. The apparatus for detecting a driver status may include an information acquisition unit (10) acquiring driver's vehicle driving information, driver's vehicle operation information, and driver status information, a calculation unit (20) calculating a driving load indicated by converting a factor obstructing safe driving into a numerical value, based on the information acquired by the information acquisition unit (10), a determination unit (30) determining the driving load calculated by the calculation unit (20) and comparing the driving load with a preset load margin, and a warning unit (40) warning the driver when the determination unit (30) determines that the calculated driving load exceeds the preset load margin. The apparatus and method for detecting a driver status determine whether a driver is driving safely by knowing mental and physical states of the driver, and guide, if determining that the driver is not in a safe driving state, the diver to drive safely by displaying warning, giving warning sound, reminding the driver by vibration, forcibly controlling the vehicle or other methods so as to protect the driver.

The invention discloses a distributed computation based voltage stability assessment method of sub-networks in an interconnected power network. The distributed computation based voltage stability assessment method comprises the following steps: firstly establishing a simplified external network model which only reserves a regional interconnection line on sub-networks in the interconnected power network; then calculating load margin by a continuation power flow (CPF) method in the main sub-network performing voltage stability assessment calculation, and then calculating by a Newton load flow method under coordination of the other neighboring sub-networks; and by means of voltage information exchange and coordination calculation of boundary nodes in outer loop, continuously correcting equivalent injection power of the boundary nodes outside the sub-networks so as to finally and locally obtain the sub-network load margin which is consistent with the result of whole network unified computation at the main sub-network. The voltage stability assessment method has the beneficial effects that by adopting the simplified external network model of the sub-networks, the Ward equivalent process is avoided so as to reduce the participation degree and calculated quantity of a coordination layer; the calculation mode is basically consistent with that in the current EMS (energy management system), and the independent calculation precision of each sub-network is higher; and voltage stability support and impact of an external power network on an internal power network can be better considered.

The invention, which belongs to the technical field of the power system stability analysis and control, discloses a voltage stability evaluation method with consideration of load growth and new energyoutput randomness. With consideration of the influence on the voltage stability evaluation by load growth and new energy output randomness, the invention provides a voltage stability evaluation method to convert an uncertain problem into several deterministic problems for solution. According to the method, on the basis of historical load data, load nodes are classified by using an improved K-means clustering algorithm; expectation of random load growth is defined based on a load prediction result; according to a load growth direction and probability distribution of wind power and photovoltaicoutputs, a load growth direction and a power output sample are obtained by using Latin hypercube sampling; and then with a continuous power flow, deterministic voltage stability load margin calculation is carried out on all samples to obtain statistical characteristics of the margin, and thus a probability evaluation result is obtained.

The invention discloses a calculation method and system of a road emergency evacuation capability index system. The method comprises the following steps of: detecting and acquiring the actual speed of a road, the actual flow of the road and the time occupancy ratio by a microwave detector; and acquiring the unblocked reliability, the travel time reliability and the load margin of the road according to the actual flow of the road and the time occupancy ratio. With the steps, the emergency evacuation capability of the road can be evaluated by adopting the speed, the unblocked reliability, the travel time reliability, the load margin and other parameters. By the invention, traffic management personnel know the utilization rate of road resources in the space and accurately grasp the traffic volume held by the road; and the calculation method has important guidance significance on the rescue, the conduct and the dredge of emergencies.

The invention relates to a method for optimizing electricity network output power in the technical field of electrical engineering, comprising the following steps: calling real-time data and net rack basic parameters of an SCADA database to form tidal data cross-section files; then calling load prediction system data and obtaining load growth mode of the next stage; converting the format of the tidal data cross-section files and the load prediction data to generate output mode optimized format data of the exertion mode of the generator; then carrying out optimization process on the exertion mode of the generator and outputting an optimum proposal; formulating an exertion plan of the generator according to the optimum proposal and implementing the generation exertion mode plan. In the invention, with the optimum proposal of the invention, the purpose of fast and effectively improving transmittable capacity of the power system and strengthening stability level of network voltage can be achieved for the power system transmission.

Given the current operating condition at each bus from real-time database, from the short-term load forecast, or from near-term generation dispatch, we present a method for real-time contingency prediction and selection in current energy management systems. This method can be applied to contingency prediction and selection for the near-term power system in terms of load margins to collapse and of the bus voltage magnitudes. The propose algorithm uses only two tangent vectors of power flow solutions and curve fitting based techniques to perform look-ahead load margin and voltage magnitude simultaneously. Therefore, it can overcome the traditional snap-shot contingency analysis methods. Simulations are performed on IEEE 57 and 118-bus test systems to demonstrate the feasibility of this method.

The invention provides a charging plan making method based on an electric vehicle battery swap station time sequence response model. The method comprises a step of establishing a backup battery control ability model in a battery swap station for the characteristic of an electric vehicle swap model, establishing a battery group state vector in the battery swap station, grouping battery group controlled states to obtain corresponding state vectors, and determining each state battery group number, a step of obtaining the load margin of the backup battery group in the battery swap station through recursive simulation, comprising calculating the battery swap station load margin of a t time and calculating following time load margin belt according to the actual load of the t time battery group, a step of proposing the making method of a battery swap station service provider charging plan with the combination of the load margin belt of the backup battery group in the battery swap station and the target load determined by a grid operation requirement under the premise of satisfying an electric vehicle swap requirement and a grid operation requirement. On the basis of satisfying the swap requirement, the reasonable regulation and control of the backup battery group charging time and charging quantity is realized, and the economic and efficient operation of the battery swap station is realized.

The invention discloses a centralized control method of large-scale electric automobile grid-connected charge and discharge. Firstly a nine-area diagram is divided on a U-mu plane formed by the low voltage side bus voltage amplitude U of an electric automobile centralized charge and discharge station and a power grid load margin index value mu according to the upper and lower limits of the reasonable operation range of two variables, and the control strategy of the corresponding electric automobile charge and discharge behavior of each area is formulated; then real-time operation data closely related to the power grid voltage stability are inputted according to a trained support vector machine optimal model so that the current maximum load parameter prediction value of the power grid is acquired, and the current load margin index value is calculated; and the area of the current operation point in the nine-area diagram is determined by combining the real-time value of the charge and discharge station low voltage side bus voltage amplitude, and then the electric automobile charge and discharge behavior is controlled according to the control strategy of the area so that the voltage stability of the power grid in large-scale electric automobile charging and discharging can be effectively guaranteed, the peak shaving effect can be realized and safe and stable operation of the power grid can be maintained.

The invention discloses a continuous power flow method of an alternating current and direct current power system considering wind power randomness. Specific to the problem existing in stability calculation of a static voltage of a wind power plant-containing alternating current and direct current hybrid power transmission system, a Monte carlo method is adopted creatively to obtain a function relation between wind power output and voltage collapse point load margin through fitting; a calculation formula of voltage collapse point load margin expectation is deduced according to an air speed weibull distribution function, a relation between wind power output and power and a fitted function; the effectiveness of the method is verified on an improved IEEE9 node system; compared with the conventional Monte carlo method, the continuous power flow method disclosed by the invention is higher in accuracy and higher in speed; influence to the voltage collapse point load margin expectation from a direct current variable control value and air speed probability distribution parameters k, c values is further analyzed; and the method also can perform analysis on load margin of different load output directions conveniently, so that a direct current control value can be reasonably set by an operator according to the current air speed distribution condition so as to regulate an operating way favorably.

The invention relates to a voltage stability probability assessment method based on scene partitioning and semi-invariants. The invention provides a voltage stability assessment method considering renewable energy output randomness by considering the influence of large renewable energy output fluctuation on the calculation precision of a conventional semi-invariant method, and the method comprisesthe following steps: firstly, discretizing the probability density function of each random variable to generate a plurality of initial scenes; secondly, dividing the initial scene set into a plurality of subsets by adopting a scene partitioning technology, and limiting the output fluctuation range of the renewable energy sources in each subset; thirdly, for each scene subset, calculating the probability distribution of the load margin by adopting a semi-invariant method according to the sensitivity of the load margin to the node injection power; and finally, obtaining the overall probabilitydistribution condition of the load margin according to a full probability formula. According to the method, the linearization error between the output random variable and the input random variable canbe effectively reduced, and the calculation precision of a conventional semi-invariant probability assessment method is improved.

A method for visualizing a probabilistic quiescent voltage stability domain comprises the steps of: acquiring an average value of a new energy power generation output, screening fault scenarios, and obtaining a serious fault set; selecting any fault scenario from the serious fault set, and establishing a voltage stability probability evaluation model based on the uncertainty of new energy power generation output; obtaining a cumulative probability distribution function of a load margin according to the voltage stability probability evaluation model; calculating a margin sorting index of a given probability in the fault scenario according to the cumulative probability distribution function of the load margin; repeating the above steps until the margin sorting indexes of all fault scenariosare obtained; and sorting the fault scenarios according to the margin sorting indexes. The method can truly and comprehensively consider the probability characteristics of new energy, effectively discriminates and sorts the quiescent voltage stability of the fault scenarios under the influence of random factors, and can accurately determine the optimal operating region of the given instability probability by setting the margin sorting index and constructing the power system probabilistic voltage stability domain based on the fault set.

The invention discloses a voltage stabilization prevention and control method based on the reactive storage sensitivity of generators, and belongs to the technical field of power system steady-state stability prevention and control. The method comprises the steps that a major failure set is determined, and key generators under major failures are determined; the reactive storage sensitivity of control variables on the key generators under the major faults is calculated; most sensitive control variables corresponding to all control types are selected to form a participating control set, and then a quadratic programming optimal control model is established; the quadratic programming optimal control model is solved, and a prevention and control scheme is determined. By means of the method, the reactive storage sensitivity of the generators can be determined without the calculation of load margin sensitivity, and the reactive storage sensitivity of the generators become more simple and visual; quadratic programming is carried out after the most sensitive control variables corresponding to all the control types are selected to form the participating control set, the established quadratic programming optimal control model is good in adaptation and robustness, and the calculation effectiveness of the quadratic programming problem is improved.

The invention provides a rolling schedule optimization method based on a comprehensive equal load function. The rolling schedule optimization method includes the steps that firstly, a load function value of each pass is calculated according to initial thickness distribution, and accordingly, an initial load margin value is obtained; secondly, the outlet thickness of each pass is calculated according to the initial load margin value; thirdly, the practical load margin of the tail pass is calculated according to the output thickness of the last but one pass and the finished product thickness; and fourthly, if the deviation exists between the practical value of the load margin of the last but one pass and the initial load margin value, iterative calculation is conducted again according to the second step according to the corrected load margin till the deviation between the practical value of the load margin of the last but one pass and the correction value meets the precision requirement. At the moment, the thickness values of all passes and corresponding pressure values form the needed optimal reduction schedule, and the correction value of the current load margin is the optimal load margin of the schedule. By means of the rolling schedule optimization method based on the comprehensive equal load function, real-time optimal calculation of the reduction schedule can be achieved very effectively, and high project application value is achieved.

The invention relates to a voltage stability prediction method for solving the single-time cross-section problem. The method comprises the following steps: 1) the voltage phasor and the current phasor of each load node at different load growth rates lambda are acquired; 2) the voltage phasor and the current phasor are taken as the measurement quantity of PMU, and parameters of an external system equivalent model of each load node in each period are acquired through identification including the least square method; 3) an impedance index LZ, a first load margin index Lbs and a second load margin index Lbss are acquired through calculation according to the parameters of the external system equivalent model; 4) and a voltage stability prediction index LVSPI is obtained according to the second load margin index Lbss and a sensitivity coefficient Csen based on the second load margin index Lbss. Compared with the prior art, the method of the invention has the advantage that nodes of a system which are most likely subjected to voltage unstability can be found out more accurately to buy time for the voltage stability control so as to improve the voltage stability control accuracy and other advantages.

The invention discloses a comprehensive energy system risk identification method based on multi-energy flow fault coupling propagation, and relates to the field of comprehensive energy safety analysis, which comprises the following steps: 1) respectively establishing mathematical models of a power system, a thermodynamic system, a natural gas system and electric thermal coupling equipment; 2) designing a risk identification system: putting forward a multi-dimensional risk identification index system for the multi-energy type contained in the comprehensive energy system; 3) calculating and analyzing a load margin optimization model of the electric thermal coupling system by combining a comprehensive energy network power flow optimization algorithm; and 4) based on the risk of load margin loss probability, determining a key branch, a node, a coupling propagation path and a key energy hub for mutual conversion between heterogeneous energy flows of the energy transmission network in the comprehensiveenergy system. The invention provides a comprehensive energy system risk identification method based on multi-energy flow fault coupling propagation. The safety, flexibility and reliabilityof social energy supply are improved.

The invention discloses a real-time estimating method for load margin of thermal power generating units. The real-time estimating method includes the steps of collecting design values of various influence factors of the thermal power generating units of a power plant within 12 months and running values of the thermal power generating units under different loads; by a BP (back propagation) neural network process, training out combined weight coefficients of difference values between design values of the influence factors and actual running values to different values between design values of load of the thermal power generating units and actual running values of load, acquiring difference values between design values of different influence factors of the power plant within one month and the maximum actual running value; acquiring real-time rate values of load regulation of the thermal power generating units through the BP neural network by the above steps; calculating the maximum adjustable load values of the thermal power generating units, and taking the maximum designed load values as the maximum adjustable load if the calculated maximum adjustable load values are larger than the maximum actual design load. The real-time estimating method can assist in learning the real-time power generation capacity of the power plant, so that power outputs of the thermal power generating units in a power grid can be adjusted in time according to real-time conditions thereof.

The invention discloses a three-stage progressive fault screening and sorting method for large grid off-line voltage stability assessment. The method comprises the steps that at the first stage, pre-screening is carried out by defining a voltage stability importance index to form a key expected fault set; at the second stage, a sensitivity-based load margin estimation method and a minimum singularvalue method are combined to quickly select serious faults from the key expected fault set; and at the third stage, unstability faults are identified through fault-type continuous power flow, and a conic fitting method is used to calculate the stability margin of other serious faults and sort the other serious faults. According to the invention, the efficiency of fault screening and sorting can be effectively improved, and the method is suitable for large grid off-line voltage stability assessment.

The invention relates to an electric automobile V2G control method based on an intelligent charging pile. The electric automobile V2G control method based on the intelligent charging pile comprises the following steps: acquiring historical load data information of the current control area through a user electricity information acquisition system, predicting the conventional electrical load of thearea on that day and generating a load curve; according to the generated load curve, dividing peak and valley time; calculating the load margin of each sub-time; acquiring battery information accessedinto the electric automobile by the charging pile and through a battery management system, acquiring related information such as the charging requirement of the user by a user interface, and determining user access time ai, user departure time Li and charging time TEV, i, wherein the charged state of the battery has upper and lower limit in order to guarantee the health of the electric automobilebattery, and the whole and charging and discharging process is conducted in the interval; and grouping a vehicle group according to that the user access time ai is in the peak or valley time. According to the flow of the control method, a centralized control center does not need to perform real-time communication and control, so that communication burden and control difficulties are reduced.

The invention discloses a parallelization calculation method for the load margin of an electric system. The method includes the steps that a second derivative based on a load parameter is adopted forestimating an initial value, so that a right feature vector initial value g0 and a load margin initial value lambda0 corresponding to a critical point initial value x0 and a zero feature value are obtained; based on the parameters, a correction equation set corresponding to a direct nonlinear equation set is constructed and split into four same-coefficient low-dimension matrix linear equation setsthrough order-reducing conversion; based on CPU-GPU mixed architecture, Jacobi and ILU two-stage preprocessing and a BICGSTAB iterative solving method are combined, the linear equation sets after order reducing are solved through parallelization, and accordingly the load margin of the electric system is rapidly solved. With the method, the correctness of the solved load margin is guaranteed, calculation speed is high, and load margins of some systems which cannot perform convergence on continuous power flows can be calculated.

The invention discloses a probability maximum load margin multi-target optimization model of an electrical coupling system and a solving method of the optimization model, and relates to the field of multi-energy-flow system operation control. The method includes the following steps that the power system maximum load margin and the natural gas system maximum load margin of the electrical coupling system serve as multiple targets, the uncertainty of wind power input is considered, constraint conditions of a power network, a natural gas network and an EH are considered, and a mathematical model of probability maximum load margin multi-target optimization of the electrical coupling system is established; the multi-target optimization model is solved on the basis of SRSM, the Newton method, NSGA-II and the maximum satisfaction decision mixed algorithm, and the optimal compromise scheduling strategy, corresponding flow distribution and other data information are obtained. The method is suitable for the development trend of energy interconnection, and can ensure the high-efficiency and environment-friendly operation of a multi-energy-flow system.

The invention discloses a load torque margin based zone area state analysis method of a power distribution network. The load torque margin based zone area state analysis method comprises the following steps of simplifying a grid structure to single-radiation topological types of all load sets hung on a trunk line in a distribution way, wherein the grid structure is a radiation type or adopts other emanant structural types in a zone area of the power distribution network, and branch lines of the zone area are expressed by a large load of a set on a connection point of the trunk line; calculating a load torque value F under a working condition; selecting a circuit model with maximum wire diameter in the trunk line as a reference circuit type of the zone area; acquiring a load torque threshold value F under a corresponding power factor; and solving the load torque margin Delta F of the zone area, thereby obtaining each load margin state possibly severing as an access point of the power distribution zone area according to the load margin Delta P. On one hand, the load torque margin based zone area state analysis method disclosed by the invention can be used for selecting an appropriate load access position, on the other hand, the construction plan of the zone area can be conveniently incorporated into a power distribution network rolling plan, and the life of users and stable household economic development of the zone area are ensured.

The invention discloses an electricity-gas coupling system probability continuous power flow modeling and solving method, relates to the field of safe and stable operation of a multi-energy flow system. The method includes the following steps: establishing an electricity-gas coupling system probability continuous power flow model; and applying a prediction-correction method to gradually approach acritical operating point of a system to calculate a maximum load margin of a power network and a natural gas network in the electricity-gas coupling system. The research conclusion can be applied tothe electricity-gas coupling system of an electric power system containing wind power, through analysis and calculation of the maximum load margin of the power network and the natural gas network, theproblem of a wind power plant access system in static safety stability of the electricity-gas coupling system can be solved, and necessary reference information can be provided for related operationdecision-makers. The method provided by the invention adapts to the development trend of energy interconnection, and can ensure the safe, efficient and environment-friendly operation of the multi-energy flow system.

A method for screening and sorting quiescent voltage stability faults, comprises: acquiring an average value of a new energy power generation output, screening fault scenarios, and obtaining a seriousfault set; selecting any fault scenario from the serious fault set, and establishing a voltage stability probability evaluation model based on the uncertainty of new energy power generation output; obtaining a cumulative probability distribution function of a load margin according to the voltage stability probability evaluation model; calculating a margin sorting index in the fault scenario according to the cumulative probability distribution function of the load margin; repeating the above steps until the margin sorting indexes of all fault scenarios are obtained; and sorting the fault scenarios according to the margin sorting indexes. The method can truly and comprehensively consider the probability characteristics of new energy, effectively discriminates and sorts the quiescent voltagestability of the fault scenarios under the influence of random factors.

The present application discloses a load balancing method and device for a monitoring server and a load balancing method and device for a server. The load balancing method for the monitoring server ina specific embodiment includes: monitoring a processing request received from a terminal and forwarded by an overload server in a server cluster; determining whether a preset light load condition issatisfied, wherein the preset light load condition includes that the load of each server is lower than the preset light load threshold of the corresponding server; in response to determining that thepreset light load condition is satisfied, determining the load margin information of each server according to the load of each server; and transmitting the determined load margin information to a terminal in order that the terminal transmits the processing request according to the received load margin information. The embodiment enriches the load balancing way.

The invention discloses a method for evaluating the load capacity of a large-scale power transformer under extremely cold conditions. The method includes the steps of calculating a winding hot-spot coefficient H of a transformer; estimating the hot-spot temperature of the transformer under extremely cold conditions; and establishing a transformer load capacity evaluation model by taking a currentload ratio of the transformer as an additional evaluation parameter; and evaluating the load margin and overload capacity of the transformer. The method of the invention reduces the downtime, improvesthe overhaul efficiency, and reduces the labor cost of enterprises.

The invention discloses a load margin calculation method and system for an electrical coupling system based on continuous multi-energy flow. The conventional load margin calculation does not consider the primary energy supply of a gas generator set and the operation constraint of a natural gas system. The technical scheme comprises the following steps: establishing a multi-energy flow model considering the safety constraint of the electrical coupling system, including the multi-energy flow model of the natural gas system, a power system and the gas generator set; and proposing a continuous multi-energy flow calculation method to solve the relation curve between the node pressure of a gas network, the node voltage of a power network and the load margin based on the continuous power flow and the load growth parameters so as to calculate the system load margin. According to the method, the load margin of the electrical coupling system can be determined and the influence of the safety constraint of the natural gas system on the load margin can be analyzed so as to provide the reference for adjustment of the operation state of the natural gas system and have an important significance for the online evaluation of the system static stability and is helpful for the system dispatcher to monitor the operation stability of the system.

The invention provides a method for evaluating the load margin of a photovoltaic power generation compensating peak. The method comprises the steps of predicting the annual maximum load of the next year by use of a straight-line equation weighing and fitting method and predicting the daily maximum load curve of the next year according to the degree of deviation of the daily maximum load curve of the last year, defining a photovoltaic peak clipping rate and obtaining a photovoltaic load cumulative distribution probability curve needing photovoltaic compensation when the daily load reaches the peak load, meanwhile, calculating the cumulative distribution probability curve of photovoltaic power output according to the photovoltaic power output data of a power grid typical day, discretizing the photovoltaic load cumulative distribution probability curve and the cumulative distribution probability curve of photovoltaic power output, and obtaining the probability that the photovoltaic power output is capable of satisfying the photovoltaic load under the circumstance of a certain photovoltaic peak clipping rate by use of a convolution differential calculation method; the defect that a photovoltaic power output-containing load prediction method only provides a certain result is overcome, the case of relatively high photovoltaic permeability is considered, the requirement of uncertain risk analysis of the power market is met, and a feasible new idea is provided with a photovoltaic system-containing power distribution network planning.

The invention discloses a road section traffic state discrimination method based on checkpoint data. The road section traffic state discrimination method is characterized by comprising the steps of: step 1, performing data preprocessing; step 2, calculating road section historical basic parameters; step 3, calculating a road section smooth-passing rate and a road section load margin at each moment; step 4, rating traffic state grades; step 5, extracting the road section load margin M and the road section smooth-passing rate O in current data; step 6, and judging traffic state grades. The adopted road section traffic state discrimination method disclosed by the invention processes and analyzes the checkpoint data, reflects traffic state information by adopting the two parameters of road section load margin and the road section smooth-passing rate, finally calculates to obtain a membership degree of the current traffic state to each traffic state of the road section, can express the roadsection traffic state information more precisely, and has better reference significance.

The embodiment of the invention provides a load margin evaluation method and system for an AC-DC hybrid power system. The method comprises: establishing a load flow calculation model of the AC-DC hybrid power system containing VSC-HVDC; and in the load flow calculation model, optimizing VSC control parameters based on a particle swarm algorithm to calculate the load margin of the AC-DC hybrid system based on an optimal continuous load flow calculation method. The embodiment of the invention provides a load margin evaluation method and system for an AC-DC hybrid power system. A load flow calculation model of an AC-DC hybrid system is established, VSC control parameters are optimized according to a particle swarm algorithm, the optimal continuous power flow is introduced to perfect and solvethe constructed power flow model, so that the evaluation of the load margin of the AC / DC hybrid system is realized, and a specific way for optimizing the load margin of the AC / DC hybrid system is provided while the voltage stability and the load capacity of the AC / DC hybrid system are effectively evaluated.

The invention provides an evaluation method and system for short-term voltage stability of a power grid. When a power grid operation state monitored in real time by a power grid relay breaks down, a monitoring bus voltage, a load bus current and a real-time relative power angle detected in real time by PMU measurement of the power grid are substituted into a real-time power grid parameter identification equation which is built in advance, and calculation is carried out to obtain load margin; if the load margin is larger than a preset short-term voltage stability value, a voltage of the power grid is in a stable state, otherwise, the voltage of the power grid is in a breakdown state; and the PMU measurement achieves rapid evaluation and margin calculation of the short-term voltage stabilityof the power grid, and enhances on-line monitoring of a short-term voltage stability point by the power grid.