291 results about "Electrical distance" patented technology

The invention discloses a wind power station equivalent modeling method of a large-scale wind power concentration access power grid. The method comprises the following steps: based on the electrical distance between all wind power station entry points of access power grid, topology distribution, model and control mode of a wind generator in the field, adopting a coherent generator groups identification method to determine the coherent wind generator group; enabling the same coherent generator group to be equivalent as a wind generator group; adopting a weighing equivalent parameter polymerizing method to resolve all the dynamic electric parameters of the equivalent wind generator group, wherein the parameters are equivalent as a form of equivalent impedance connected the equivalent machine in series according to the static equivalence theory; resolving the relative static parameters; and based on the obtained wind power station equivalent form to develop and realize wind power stationmodeling in a PSD-BPA simulation platform. The method solves the problem of the wind power station equivalent modeling in the prior art, and provides the simulation tool for operation mode analysis and scheduling control of the power grid.

The invention discloses a full automatic pipe cutting machine. The pipe cutting machine comprises a feeding drive part, a cutting drive part, a pipe clamping part, a cutting part, an unloading part and a cutting measurement part which are sequentially arranged on an operating platform, wherein the feeding drive part conveys pipes to the cutting part by a driving wheel and a rolling wheel, then the pipes are cut off by a cutting tool driven by the cutting drive part; the driving wheel of the pipe cutting machine is driven by a stepping motor, and the lengths of the cut pipes can be accurately detected and controlled according to the electrical signals of stepping quantity of the stepping motor and the data of radius of the driving wheel; and in addition, the operating platform is also provided with an infrared distance measurement sensor, and the length accuracy of the cut pipe is jointly ensured by the electrical distance measurement signals and the movement detection signals of the stepping motor. By adopting the clamping feeding structure, the automatic cutting structure, the automatic clamping structure, the automatic unloading structure and the automatic cut pipe-length measurement and control mechanism, the degree of automation of the pipe cutting machine is improved.

Systems and methods inhibit locomotion of a human or animal target in a denial zone. Acquiring the target includes forming a prediction of at least two locations of impact on the target and testing the prediction according to criteria that may include whether the locations are within a boundary corresponding to the target and whether the locations are separated by a minimum physical and / or electrical distance.

Systems and methods inhibit locomotion of a human or animal target in a denial zone. Acquiring the target includes forming a prediction of at least two locations of impact on the target and testing the prediction according to criteria that may include whether the locations are within a boundary corresponding to the target and whether the locations are separated by a minimum physical and / or electrical distance.

The invention discloses a low-voltage power line communication network constructing method for a power meter reading system. A constructed low-voltage power line communication network comprises a concentrator, a carrier power meter and a collector; wherein the collector and the carrier power meter are used as terminals for each level; the low-voltage power line communication network construction is completed in three steps: logical layering, communication topology construction and communication routing selection; the logical layering comprises establishing logical layers according to the length of the electrical distance between the terminals in each level, and respectively marking and attributing the collector and the carrier power meter into different levels; and the communication topology construction comprises storing the IP of the two terminals and the electrical distance into the concentrator under the condition that the electrical distance of the two terminals between the upper level and the lower level is less than or equal to L, thereby optimizing the network topology. In addition, the invention adopts a communication routing reconstruction method for the carrier power meter with failure, thereby realizing the timely updating and troubleshooting of the network topology.

The invention belongs to the field for reasonably selecting lower isolation places under a large power grid serious fault, and particularly relates to an active disconnection optimum fracture surface searching method based on electrical distance. According to the method, the shortest electrical distance between nodes is obtained through a Dijkstra algorithm, and the nodes are divided into common nodes and general nodes according to the strength of electrical relations between all the nodes; according to the relations between the disconnection fracture surfaces and the common nodes, the searching of the disconnection fracture surfaces is transformed into processing of the common nodes; with the smallest active power unbalanced power in a disconnected subsystem as a target function, the common nodes are searched for based on a width precedence algorithm, and the optimum disconnection fracture surface is obtained. The method has the advantages that the requirement for high speed of online calculation is met, and the method can adapt to changes of the operating mode of the system, and the actively disconnected optimum fracture surfaces can be accurately and effectively captured.

The current invention provides a method and apparatus for wireline characterization is disclosed. The method may be implemented with any modulation protocol but is particularly suited for multi-carrier modulation protocols such as discrete multi-tone (DMT). The apparatus may be incorporated into physical or logical modems. In an embodiment of the invention an apparatus for wireline characterization in a modem with a transmit path and a receive path each configured to couple with a remote modem via a wireline in which available communication bandwidth is split into a number of independent sub-channels is disclosed. The apparatus comprises: a tone selector, a cumulative loss estimator and a shift register. The tone selector selects a subset of the number of sub-channels within the bandwidth of a received wireline communication for which subset the sum of the square roots of the corresponding sub-channel indices may be expressed as an integer power "n" of 2. The cumulative loss estimator cumulates the insertion losses across the selected subset of the sub-channels and outputs a binary value corresponding thereto. The shift register couples to the cumulative loss estimator to scale a magnitude of the binary value received from the cumulative loss estimator by an amount proportionate to "n" to obtain a scaled electrical distance estimate for the wireline. Corresponding method and means are disclosed.

The invention discloses a reactive voltage control partitioning method under wind power integration. The method comprises the steps as follows: a whole network electrical distance expected matrix considering wind electricity power probability characteristics takes the place of an electrical distance matrix under one power flow section to be used as a partitioning basis; PQ node partitioning is achieved on the basis of AP clustering; the voltage regulation sensitivity of a PV node region considering the wind electricity power probability characteristics is defined by a perturbation method; PV nodes ranked on the basis of the region sensitivity are partitioned; the regional connectivity and controllability are firstly considered in node partitioning; and meanwhile, the condition that the PV nodes are classified into a PQ region which is the most sensitive in control can be ensured to the maximal extent. An index evaluation result shows that the partitioning scheme obtained by the method obtains a good effect; and an auxiliary reference can be provided for voltage control under wind power integration.

An aiming light assembly of an imaging reader projects on a target, during an aiming mode of operation, an aiming light pattern that varies as a function of distance between a movable housing and the target. A solid-state imager captures light from the aiming light pattern during the aiming mode, and generates an electrical distance signal indicative of a target distance between the housing and the target. The imager also captures return light over a field of view from the target during a reading mode of operation after the aiming mode, and generates an electrical target signal indicative of the target. A controller processes the electrical distance signal during the aiming mode into data indicative of the target distance, and also processes the electrical target signal during the reading mode into data indicative of the target located at the target distance.

The invention discloses a high permeability distribution type renewable energy generating cluster dividing method, which comprises the steps that distribution type renewable energy power supply, load,and distribution line form an active power distribution network, and the distribution type renewable energy power supply, and a bus accessed by the load are used as the node, and the dividing of thegenerating cluster can be conducted based on the proper phasor; the characteristic vector is formed by a node power characteristic curve, a node geographic coordinate, and node electrical distance; the hour node power curve at a typical day is used as the characteristic curve of the node power; the geographic plane coordinate of the node is used as the node geographic coordinate; the voltage wattles sensitivity matrix among nodes can be calculated based on network topology and the typical day load curve; fuzzy clustering algorithm can be adopted to construct a similar matrix based on differentcharacteristics of characteristic vectors, and the distribution type renewable energy power supply generating cluster dividing can be conducted. The invention is advantageous in that the regulation and control problem of large scale renewable energy can be simplified, and the group regulation and ground control of the renewable energy can be benefited.

The invention discloses a self-adaptive dynamic equivalence method for transient rotor angle stability online analysis of a power system. The invention belongs to the power system and automation technique fields. The method comprises the following steps of: calculating a detail degree index of dynamic equivalence carried out on the power system according to a transient rotor angle stability mode of the power grid after a certain expected failure under the power grid operation condition of the previous round, and the change of the current power grid operation condition relative to the power grid operation state of the previous round; carrying out the coherent equivalence on the generator of the rest generator group, the participation factor of which is less than the dynamic equivalence index, in the transient rotor angle stability mode of the failure; remaining nodes from which the electrical distances to other generators and the failure element are less than a set value and the branches directly connected with other branches; carrying out the corresponding network simplification on the power grid; and carrying out the transient rotor angle stability online analysis of the failure of the current round according to the equivalent power grid. Therefore, the calculation speed is improved by the invention.

A method and apparatus for storing and retrieving data in a second, or higher, order prefetch architecture memory integrated circuit. The method includes storing multiple bits of data in memory cells at various electrical distances from an output buffer and retrieving those memory bits concurrently for output. By outputting the bits in a fixed burst order, according to which a bit from a memory cell closer to the output buffer is output before a bit from a memory cell farther from the output buffer, the output time of the data bit from the closer memory cell can be used to mask a portion of the transit time of the bit from the farther memory cell. The apparatus includes memory cells at various locations for storing data bits, an address decoder adapted to store and retrieve multiple bits in a fixed burst order, and a multiplexer.

The present invention discloses a voltage stability testing method based on the power transmission path. The invention settles the problem that the process for detecting the voltage stability is complicated. The method of the invention is used for detecting the voltage stability based on the power transmission path, and the method comprises the following steps: 1) executing a current computing to the electric network system, and obtaining the information of voltage, current, wattful power and reactive power of each node of electric network in the system; 2) computing a partial stability index, and confirming an assembly of the weak load node; 3) confirming the key power source node and path participation node according to the electric distance information, and generating an assembly of the weak power of the system; 4) respectively equalizing each weak path, confirming the weakest power transmission path and obtaining the index of voltage stability of system; and 5) confirming the reactive power holding index of the system, and confirming the voltage stabilization degree of the system and whether a corresponding control measure should be executed according to the obtained index of the voltage stabilization and the reactive holding index.

The invention discloses an optimal configuration method for fault current limiters. An area with high risk of failure in simultaneous phase commutation is judged by using a multi-infeed DC interactionfactor. During the configuration of an SRFCL device, the average electrical distance from a current limiting node to the DC converter stations in the area with high risk of failure in simultaneous phase commutation is calculated, and the priority of the current limiting node is determined to avoid large-range search. Meanwhile, the suppression effect of SRFCL on DC commutation failure is considered. Therefore, an SRFCL optimal configuration scheme taking both short-circuit current limiting and commutation failure suppressing into account is realized. The method is helpful for power system planners to grasp the influence of SRFCL installation and configuration on the phase commutation failure of a multi-infeed DC system and visually determine an SRFCL installation area. The indexes in thearea can be displayed in order during calculation. The method is easy to implement. Decision support is provided for the optimal configuration method of SRFCL in the multi-infeed DC system.

The invention relates to a flexible half-wave power transmission system based on a power electronic commutation technology and a tuning method of the system. The power transmission system comprises a long-distance power transmission line and a power transmission line flexible tuning device, wherein the flexible tuning device comprises a frequency conversion type flexible tuning device and a synchronous compensating type flexible tuning device; the frequency conversion type flexible tuning device is used for constructing a frequency conversion type half-wave power transmission system by adjusting the power transmission frequency on the basis of a power electronic frequency conversion principle and the synchronous compensating type flexible tuning device is used for constructing a synchronous compensating half-wave power transmission system by adjusting the equivalent electrical distance of the power transmission line on the basis of a synchronous compensating principle of a power electronic inverter. Half-wave power transmission has the advantages of far transmission distance, good voltage stability at first and tail ends, infinitely great theory limit of transmitting power, no reactive compensation devices and intermediate switching stations and the like. The economical benefit of half-wave power transmission is even superior to that of direct-current transmission, and the flexible half-wave power transmission system is particularly suitable for point-to-point, high-capacity and ultra-long distance power transmission and distribution and has strong competitiveness on transcontinental and transnational power transmission and power supply for remote regions.

The invention discloses a multi-infeed HVDC (high-voltage direct current) system partitioning method based on the mounting of fault current limiters. The fault current limiters are mounted on proper alternating current lines, so that a multi-infeed HVDC system is partitioned into a plurality of regional power grids which are isolated from one another by the fault current limiters; when the alternating current system in a certain regional power grid in the multi-infeed HVDC system is subjected to a short circuit fault, the impedance of the fault current limiter is increased to a rated value, so that an electrical distance among the regional power grids can be increased, and the short circuit fault can be prevented from being transmitted to other regional power grids from the faulted regional power grid; and the alternating current bus voltage in other regional power grids is increased, the phase change failure duration of each HVDC line in each of other regional power grids can be shortened, and the recovery speed of the transmission power of the direct current lines can be increased, so that the problems of power imbalance and flow transferring of the alternating current system caused by the simultaneous phase change failure of the HVDC lines in the multi-infeed HVDC system can be relieved, and the safety and stability of the multi-infeed HVDC system under the condition of the short circuit fault of the alternating current system are improved.

The invention discloses a multifunctional construction safety monitor, which is characterized in that the monitor is composed of a dust sensor, a combustible gas sensor, a carbon dioxide CO2 sensor, anear electrical distance sensor, a temperature sensor, a display screen, a DSC digital signal controller, a GPRS / Lora wireless module and a voice module connected by an MCU; the DSC digital signal controller is connected with a smart helmet / 3D spatial positioning tracking wireless communication module, an acceleration sensor and a gyroscope; the MCU sends monitor data by the GPRS / Lora wireless module to a cloud monitoring system platform through the Internet of Things. Compared with the prior art, the monitor has the advantages of simple structure and small volume, is convenient for on-site construction personnel to carry around, and can timely and accurately monitor the working environment of the construction personnel to perform corresponding alarms, thereby effectively preventing or reducing the damage of the safety hazards existing on the construction site to the on-site construction personnel.

The invention provides a unit load dynamic reactive response based minimum boot order optimization method. The method comprises the steps of determining a weak spot in a heavy load region of a power system; determining an electrical distance index and a dynamic reactive response quantitative index; calculating response effect indexes influencing system voltage of each generator in the power system separately; determining the boot order of the generators according to index values of the response effect indexes; controlling the startup and shutdown of the generators based on the boot order, and detecting the steady state of the weak spot, wherein the actual startup-shutdown order of the generators when the weak spot reaches a critical steady state is the minimum boot order. Compared with the prior art, the invention provides the unit load dynamic reactive response based minimum boot order optimization method; the effect degrees for the system voltage in the shutdown processes of the generators are clearly determined, so that the generator boot order arrangement policy at the minimum machine halt mode is greatly improved, and the method is relatively high in adaptability.

Memory banks are assigned to the memory map of a common processor in an order corresponding to a physical characteristic of the respective memory bank, e.g., a physical distance to the processor and / or an electrical distance to the processor. In this way, the operating frequency of the processor can be increased beyond conventionally guaranteed limits at the expense of abandoning the farthest memory banks when not necessary for a particular application. Similarly, abandonment of the farther memory banks in accordance with the principles of the present invention allows operation of the processing system at higher temperatures and / or lower power voltages. In another embodiment of the present invention, wait states may be added to accesses to the farther memory banks such that the closest memory banks may be operated at the highest possible performance level, e.g., without any wait states. The performance of the individual memory banks may be monitored and a wait state table adjusted to adjust to environmental conditions such as temperature and / or power voltage.

The invention discloses a comprehensive performance index-based high-permeability distributed power supply cluster division method, and relates to the technical field of power distribution network planning and control of a renewable energy power supply. A cluster division index system and a cluster division effective algorithm are proposed; the cluster division index is defined as a comprehensiveperformance index; the comprehensive performance index comprises an electrical distance-based modularity index <rho>, a cluster reactive balance degree index formula which is as shown in the specification and a cluster active balance degree index formula which is as shown in the specification; for adapting the calculation expression of the comprehensive performance index system and the objective demand of cluster division, the cluster division effective algorithm performs distributed power supply cluster division based on a genetic algorithm; meanwhile, by improving the basic genetic algorithmand according to the network adjacent relation, a chromosome coding mode is designed; and adaptive crossed mutation probability is adopted. The comprehensive performance index-based high-permeabilitydistributed power supply cluster division method has the advantages as follows: complementarity between nodes and cluster capacity of self-government can be fully played, so that large-scale renewable energy consumption and control can be promoted.

An active power distribution network distributed power supply partition in-situ voltage control strategy setting method comprises the steps of: determining a system structure and parameters accordingto a selected active power distribution network; calculating an electrical distance matrix formed by electrical distances between nodes of an active power distribution network; obtaining the optimal partition numbers of the active power distribution network through determination of the size of the feature value of the electrical distance matrix; employing the K-means clustering algorithm to perform clustering partition for the electrical distance matrix to obtain a power distribution network partition result; according to the active power distribution network structure and the parameters, based on the partition result, establishing an active power distribution network distributed power supply partition in-situ voltage control strategy setting model; covering the active power distribution network distributed power supply partition in-situ voltage control strategy setting model to a second-order cone model; employing a mathematical solver for solving the second-order cone programming toperform calculation and solution of the second-order cone model of the active power distribution network distributed power supply partition in-situ voltage control strategy; and outputting a solutionresult. The formulation and the optimization of the distributed power supply in-situ voltage control strategy are simplified.

The invention discloses a clustering algorithm-based radial distribution network reactive power optimization method, which comprises the following steps: (1) constructing a node incidence matrix A by a network topology structure of a power distribution network; (2) determining an electrical distance matrix D between nodes by known electric power network parameters and the incidence matrix A obtained in the step (1); (3) preprocessing the distance matrix D to obtain a two-dimensional constructed map X, and clustering and grouping various coordinate points by a clustering algorithm; and (4) selecting a reactive power compensation point from each category group and carrying out optimal computation by a standard particle swarm algorithm. Region partition is carried out on the power distribution network by the clustering algorithm; the number of partitions is equal to that of selected compensation points; and then the compensation point is selected from each region, so that the problems of uneven compensation point distribution, overlapped compensation range and the like are solved.

The invention relates to a time difference method based adaptive half wavelength line differential protection method. As the electric distance of half wavelength power transmission is long, obvious actuation time difference between protective starting elements at two sides of the line exists after faults occur. According to the wave transmission principle, the position of a fault point can be estimated according to the actuation time difference of the protective starting elements at two sides of the line. Voltage and current of the protective installation positions at two sides of the line can be compensated to the fault point according to a long line equation, so as to obtain a current value of the fault point, and then differential current is calculated. Sensitivities for fault differential protection criterions of different points of the line are different, and brake coefficients and threshold values of differential protection are changed according to different adaptions of the fault point positions, so as to ensure that differential protection has sensitivity for the whole line.

The invention relates to a method for determining a level of a material interface in a tank, by means of a radar level gauge system comprising a transceiver; a probe for guiding a transmitted electromagnetic signal towards the material interface. The probe comprises a first plurality of reference impedance transitions located above the interface at known physical distances from a reference position, and a second plurality of reference impedance transitions located below the interface at known physical distances from the reference position. The method comprising determining electrical distances to the first and second plurality of reference impedance transitions based on a signal reflected by the reference impedance transition, determining, a first and a second approximation function relating the first and second sets of electrical distance values to the physical distances; and determining the level of the material interface based on the first approximation function and the second approximation function.

The invention provides a sheet feeding unit and an image forming apparatus capable of reducing an electrical distance, even for a plurality of sheet kinds, capable of providing a sheet bundle carried in a sheet carrying component which is changed into stable relative to an environmental change or a period change, and capable of highly-speed and practically separating the sheet feeding unit in one piece with high reliability. An electrical scraper (33) is contacted with an endless belt (32); a small clearance G for applying a charge to a surface (32a) of the endless belt (32) is formed by discharging between the electrical scraper (33) and the endless belt (32), simultaneously forming a front end part (33a) of a clamping portion with the endless belt (32); and a basic electrical width H formed by a width N of the clamping part and the small clearance G is less than one half (1 / 2P) of a cycle length of an alternation charge applied to the endless belt (32) by the electrical scraper (33) so as to be less than the electrical width of the charge electrified with the same polarity in a surround moving direction of the endless belt (32).

A method for automatically selecting key sections on a load side of an electrical partition of a power grid includes the steps that the electrical partition is acquired by the adoption of a method for automatically finding the electrical partition based on electrical distance, and power transmission channels are looked up from an unsafe power transmission line in the electrical partition and used as the key sections on the load side, wherein the power transmission channels are closely related with the unsafe power transmission line, and thermal stability and voltage stability problems are prone to occurring in the power transmission channels. The method can online automatically acquire the key sections with outstanding thermal stability and voltage stability problems on the load side inside the electrical partition of the power grid, can complement and perfect an existing system for automatically finding the key sections, can adapt to increasingly variable operation modes of the power grid, and can improve accuracy and practicality for automatically finding the key sections of the power grid.

The described method and system provide an antenna feed for a slot antenna that may be patterned into a solar-reflective glazing layer with a virtual ground that is a short electrical distance from the antenna. One implementation of the present invention provides an antenna feed for a slot antenna patterned into the solar-reflective glazing used in a vehicle windshield. Because the antenna feed may incorporate a virtual ground that is a short electrical distance from the slot antenna, antenna performance may be improved over conventional on-glass vehicle antenna systems which use the vehicle chassis as a ground. Furthermore, patterning the slot antenna into the solar-reflective glazing layer and using a virtual ground in the antenna feed provides flexibility in antenna placement.

The invention provides a voltage wattless control partition method based on a generator electrical distance. The voltage wattless control partition method comprises steps that: a shortest path from generators to electrical buses is calculated based on a Dijkstra algorithm, an electrical distance from the generators to the electrical buses is calculated based on a branch reactance value on the shortest path, partitions to which the electrical buses and the generators belong are determined based on the electrical distance, a number of the partitions is consistent with a number of the generators, automatic partition merging is carried out to realize an optimal number, partition belonging of the electrical buses at partition boundaries is adjusted according to sensitivity of a generator wattless power to voltage amplitudes of the electrical buses at the partition boundaries. The voltage wattless control partition method divides an area grade electrical network into a plurality of weak tie sub-net according to a wattless decoupling principle, so wattless influence on an adjacent electrical network is reduced to a maximum degree when individual voltage wattless control of each subnet is carried out.