6390 results about "Transient state" patented technology

A method for predicting risk and designing safety management systems of complex production and process systems which has been applied to an FPSO System operating in deep waters. The methods for the design were derived from the inclusion of a weight index in a fuzzy class belief variable in the risk model to assign the relative numerical value or importance a safety device or system has contain a risk hazards within the barrier. The weights index distributes the relative importance of risk events in series or parallel in several interactive risk and safety device systems. The fault tree, the FMECA and the Bow Tie now contains weights in fizzy belief class for implementing safety management programs critical to the process systems. The techniques uses the results of neural networks derived from fuzzy belief systems of weight index to implement the safety design systems thereby limiting use of experienced procedures and benchmarks. The weight index incorporate Safety Factors sets SFri {0, 0.1, 0.2 . . . 1}, and Markov Chain Network to allow the possibility of evaluating the impact of different risks or reliability of multifunctional systems in transient state process. The application of this technique and results of simulation to typical FPSO / Riser systems has been discussed in this invention.

The invention discloses a method for locating fault of power distribution system with ineffectively grounded neutral point based on transient traveling wave, which can acquire required traveling wave signals and relatively higher detection reliability by arranging equipment only on both sides of circuit. According to the actual site condition, a non-contact electromagnetic field sensor is arranged in a transformer substation to acquire transient voltage and current traveling wave, a power distribution transformer arranged on the tail end of the circuit transmits voltage-variable traveling wave to solve the problem in acquisition of tail-end voltage traveling wave signals, and the type of the fault of the circuit can be rapidly recognized according to the amplitude and the polarity characteristics of a fault traveling wave recorded by the secondary side of the transformer. The invention provides a new fault search algorithm based on the midpoint of time to solve the problem of noncontinuous wave speed of aerial wire and cable. Accordingly, the proposal can achieve the assembly and the operation of the equipment without adding extra primary equipment of the system and powering off the circuit, thus saving the cost and reducing the complex degree of the project. Practical operation shows that the method can locate a fault within a range of plus or minus 100 m.

The invention discloses a mixed MMC-based mixed direct current power transmission system, comprising a rectifying converter station and an inversion converter station, wherein the inversion converter station adopts a mixed MMC. The direct current power transmission system has the active and reactive decoupling control capacity, can transmit power to a reactive network without the phase change failure risk and has direct current fault self-cleaning capacity; under the condition that a feeding end alternating current system has a fault; the mixed MMC has the capacity of outputting a negative level by using a full-bridge submodule, the direct current voltage output by the system can be reduced under the premise of ensuring the controllability and stability of the system, the direct current voltage can be matched with the direct current voltage of a rectifying station, and the direct current power is maintained to be continuously transmitted; due to the optimization on the number of two types of submodules in the mixed MMC, the use number of power electronic components is greatly reduced and the investment cost is reduced under the condition that the mixed modularized multi-level converter meets the stable and transient operation demands of the direct current system.

The invention discloses a non-intrusive mode electrical load identification system and method. The load identification system comprises electrical load, a load identification terminal and a load monitoring main station; and the load identification terminal performs information interaction with the load monitoring main station through modes of optical fibers, an Ethernet and a wireless public network. The load identification terminal, by analyzing waveform characteristics of current, voltage, active power and the like of typical electrical equipment, defines different characteristic parameters based on a steady state process and a transient state process to establish a standard transient library, and then establishes an electrical load identification model by combination of the steady state and the transient state characteristic similarity of the electrical equipment. The identification system module is high in integration level, the terminal is smaller in size, the construction cost of the system is lower, the running and maintaining of the system are simple without affecting production and life of users; and the non-intrusive mode electrical load identification method can realize accurate identification of load types and running states of multiple paths of electrical equipment at the same time.

The present invention relates to a power system and provides a method for considering the network security constraints of in the operation of economic dispatch of power systems, which comprises the power flow constraint of branches, the static voltage stability constraint and the transient stability constraint, and provides an effective way for coordinating contradiction between the economy and security of power system operation. The security region based security-constrained economic dispatching method comprises the following steps: step 1, calculating the coefficients for the active power static security region, the cut-set voltage stability region and the dynamic security region respectively; step 2: building the models for security region based security-constrained economic dispatch; step 3: solving the unit on / off state optimal sub-problem through Social Evolutionary Programming; step 4: calculating the generation cost, the static voltage stability margin and the transient stability margin in the dispatching period; step 5: obtaining a feasible economic dispatching scheme, otherwise, return to step 3. The invention is mainly applied in load dispatching optimization.

The present invention relates to a small current grounding system fault line selecting method by wavelet package decomposition and relevant analysis, belonging to the power system relay protection technical field. The method comprises: starting the fault line selecting device and recording wave to acquire transient zero-order current on each of the feeder lines when bus zero-order voltage transient value exceeds limit; calculating energy on each of frequency bands of the transient zero-order current after wavelet package decomposition, summing the energy of transient zero-order current on all the lines according to frequency bands and selecting the frequency bands with the maximum and secondary value of energy and values as the characteristic frequency bands, applying relevant analysis method to line transient zero-order current on the selected characteristic frequency bands in order; and finally determining fault point integrating the relevant analysis results of two frequency bands. The method uses wavelet package decomposition and relevant analysis, thereby effectively using information (amplitude and phase) contained in fault transient process and reflecting differences between fault line and non-fault line to maximum degree. Principle analysis and simulations demonstrate that the method has precise and reliable line selection.

A method, system and program product for annotating a transient state of a computer displayed application enables annotation of transient applications particularly web based applications. A transient application address (or key) and state information related to an application at a transient state are stored in an annotation store along with an annotation. The annotation is related to the transient application by the application address or key. The application is automatically restored to the transient state when the annotation is requested. Optionally a screen capture of the application at the transient state is also presented.

The invention provides a low current grounding single phase earth fault diagnosis method, comprising: capturing A voltage to ground, B voltage to ground, C voltage to ground, neutral point current and entire waveform information of each zero sequence current from a steady state to a transient state then to steady state when neutral point voltage exceeds presupposed threshold; first diagnosing whether being single phase earth fault, PT fusing, ferro resonance, arc suppressing coil resonance overvoltage, or neutral point overvoltage disturbance caused by experiment; selecting lines for the earth fault. The inventive method makes full use of steady state information and transient information of electric network before and after fault, and judges the fault and selects lines according to the long term changing rule of the neutral point voltage, which is different from the traditional stable state line selecting method and the transient line selecting method, thereby being suitable for the neutral point unearth electric network and the neutral point arc suppressing coil earth electric network at the same time, and well adapts the condition of complex site, thereby ensuring fault diagnosis and correct line selection.

A system for generating accessory power from a gas turbine engine is provided by the present invention. The system includes an electronic control device for monitoring at least one parameter which provides information about an incipient change in power demand, a control valve operated by the control device for supplying bleed air from the engine during a transient state in response to the at least one monitored parameter, and a pneumatically operated device for receiving the bleed air and for generating power to operate equipment onboard an aircraft. The pneumatically operated device may be an air turbine or a pneumatically integrated generator.

The invention discloses an intelligent fault classification and location method for an ultra-high voltage direct current transmission line, and belongs to the technical field of relay protection of power systems. The method comprises the following steps of: classifying fault data by using a neural network by adopting a layered and distributed neural network model; distinguishing fault types; sending the classified data into different neural networks respectively for performing fault location; when the direct current transmission line has a fault and a sampling frequency is 10 kHz, selecting a discrete line mode voltage signal which has the sampling sequence length of 100 after the fault and performing S-transform, wherein a transform result is a complex time-frequency matrix of 51*100; solving the modulus of each element in the complex matrix to obtain transient energy distribution of the line mode voltage at all frequencies; selecting first five energy spectrums as sample properties; selecting a transfer function and a learning rule; setting proper neural network parameters for constructing a BP network model; and performing fault classification and fault location. A large number of simulation results show that the method has a good effect.

A method of distinguishing nucleotide sequences for different nucleic acid molecules including the steps of (a) mixing a plurality of different nucleic acid molecules with polymerase molecules and nucleotide molecules, wherein the different nucleic acid molecules are attached to a surface in the form of an array of nucleic acid features; (b) determining a transient state of the polymerase molecules at the nucleic acid features; and (c) identifying a subset of nucleic acid features that correctly incorporate the nucleotide molecules based on the transient state of the polymerase molecules at the nucleic acid features, thereby distinguishing the nucleotide sequences for the different nucleic acid molecules.

The invention relates to the relay protection field of a distribution network, in particular to a single-phase earth fault self-adapting selection method of a double-phase TA distribution network based on transient state zero sequence current frequency distribution. The invention is characterized in that: firstly zero sequence currents before and after failure are decomposed into wavelets and character frequency ranges of each line are reconstructed by single branches; then zero sequence current instantaneous values in reconstructed signals of each line are compared with corresponding instantaneous values of other lines through symbols; if the symbols of the zero sequence current instantaneous values are different from that of other lines, 1 is added to a counter; after all the sampling points are compared, a line with largest counter value is obtained; symbol comparison of respective reconstructed data is performed again to lines with the character frequency range of (4,0), and if points with uniform symbols account for over 60 percent and the values of the points are larger than counter values of other lines by five, then the line is estimated as a fault line; otherwise the line with largest counter value verified is estimated as a fault line. The invention can effectively utilize information included in the fault transient state process and greatly improve the reliability of fault selection.

The invention provides a detection method and a detection system of an intelligent relay protection device. Aiming at the situation that compared with the prior art, dynamic properties of the relay protection device cannot be detected effectively in an intelligent substation spot, and starting from the feature of sharing of digitalization and informatization of an intelligent substation secondary system, the detection method which regards a digit simulation system as a data source and regards synchronous working of a plurality of digitized relay protection testers is provided and the detection system of the intelligent relay protection device is constructed. Various operating situations which probably happen in a transformer substation can be simulated according to an actual electric topological structure of an intelligent substation and device parameters construction and simulation models in a lab, simulating calculation can be conducted, transient test data which have higher similarity with the actual operating situations can be achieved by transforming, the transient test data can be output in the intelligent substation spot in a playback mode, and detection of the dynamic properties of the relay protection device and checkout work of protection definite value can be carried out.

A power pool online precaution control method based on the static state and the transient safe stable mode, includes: 1) obtaining the transient state process, 2) seeking the transient state and the static state safety margins, 3) performing the pattern classification to the failure, 4) trying to the obtain the adjusting project which satisfies all the failure modes, 5) computing the participation factor of the unsafe candidate control measurement of the transient state voltage and the frequency and sorting, 6) computing the sensitivity of the participation factor of each overload candidate control measurement after the failure and sorting, 7) obtaining the new mode data after adjustment and checking the safety of the static state and the transient state. The invention performs the coordination optimization among the transient power angle, the transient voltage / frequency and the static state device overload precaution control through integrating the control measurement participation factor of each mode, obtains the optimized safe and stable precaution control measure for satisfying the practical requirement of the engineering.

The invention discloses a recognition method of on-line monitoring of power consumption of non-intrusive household appliances, and belongs to the field of recognition of the power consumption of the household appliances. By means of an intelligent electricity meter in a family close to the outdoor, instantaneous currents or instantaneous power signals are obtained, the obtained signals are processed, steady state / approximately steady state or transient state characteristics of the signals are obtained, characteristic information of the signals is compared with information in a feature library by means of the crossed weighted method, and therefore equipment which is invested or removed can be recognized. The recognition method is simple in algorithm and accurate in judgment, and does not influence normal operation of the household appliance equipment.

The invention relates to a method for testing high impedance faults, which is based on transient traveling waves and belongs to the electric system protecting and controlling technique field. The method comprises faults actuating and faults testing, wherein the faults actuating adopts transient traveling waves electric quantity to judge actuating, The faults testing is actuated through comparing the transient traveling waves electric quantity and a threshold value. The fault testing adopts fault components to judge, faults testing results are output through an algorithm of fault detection. Three algorithms are adopted in high-resistance fault judgments, which include a high frequency algorithm, a harmonic algorithm, and a fundamental wave algorithm. The three algorithms can be used in either a single end form or in combination to judge high-resistance actuating. The method can test thoroughly each main frequency band information which may be produced when high resistance faults occur.

The invention discloses a multi-parameter identification based secondary system fault diagnosing method for an intelligent substation. The multi-parameter identification based secondary system fault diagnosing method is mainly applicable to digital substation accordant with IEC61850 communication protocol. The method includes: comprehensively analyzing multi-dimensional parameters including various alarm information, telemeasuring data, telecommand states and the like of a process layer, a spacer layer, a station control layer through a network message recording and analyzing device, monitoring states of secondary devices in real time by utilizing original messages as analysis data and utilizing recording of transient state of device exception and long-term monitoring of operation states as means, and realizing fault diagnosis and state monitoring of the secondary system of the intelligent substation. The multi-parameter identification based secondary system fault diagnosing method for the intelligent substation has the advantages in two aspects including that normal states of the secondary device of the intelligent substation can be monitored, background data and maintenance reference are provided for state maintenance; exception states are identified, quick fault diagnosis is realized, effective instruction can be provided for transport maintenance, and convenience in maintenance of the substation is improved.

Power distribution networks of countries such as China and the like mainly adopt a low-current grounding method. Most faults of the low-current grounding power distribution networks are single-phase high-resistance grounding faults and low amplitude of transient capacitive current signals, short duration, and high detection difficulty are generated in a fault process so that an effective fault detection and positioning system is lacked. The invention discloses a fault detection and positioning method and system for a low-current grounding power distribution network. The system includes feeder line monitoring units, a communication terminal and a system master station. A feeder line monitoring unit wirelessly and synchronously triggers the other two phases to transmit data after a suspected grounding fault is detected. The system master station and the communication terminal adopt GPS time service. The communication terminal and the feeder line monitoring units carry out time hack through a time division multiplexing wireless communication network. The system master station collects three-phase feeder line monitoring unit data at a plurality of points through the communication terminal and detects and positions a grounding fault according to calculated zero-sequence voltage and zero-sequence current and issues a fault signal to feeder line monitoring units in front of a fault point on a fault phase so as to carry out fault indication.

The invention belongs to the field of power converter control and relates to a model prediction control method of a voltage source type rectifier when a network voltage is unbalanced. The model prediction control method of the voltage source type rectifier when the network voltage is unbalanced comprises the steps of converting three-phase network voltage and a three-phase current into network voltage and a current which are under a two-phase static coordinate system through an abc / alpha beta coordinate, obtaining network positive sequence voltage and negative sequence voltage by carrying positive and negative sequence component separation of the network voltage under the two-phase static coordinate system, calculating reference values of active power, calculating current reference values of the rectifier under the two-phase static coordinate system, and carrying out model prediction current control and selecting an optimal on-off state. The model prediction control method of the voltage source type rectifier when the network voltage is unbalanced is capable of quickly and precisely tracing the current under the two-phase static coordinate and effectively eliminating fluctuation of direct current side voltage at the same time, power quality of the system is improved, a reliable network-connected operation of the rectifier when transient state network voltage is unbalance is achieved, and dynamics and stability of the whole system are improved.

A fault inrush transient current restraining type virtual synchronous inverter and thereof is disclosed. The invention solves the problem that a virtual synchronous inverter will be burned due to inrush transient current in an extreme situation of a symmetrical fault occurring on the grid side by setting an information collection module for inverter output voltages and currents, a virtual synchronous inverting control module, a fault detection and synthesize module, a hysteresis comparison control module and a post fault clearing switch back grid-tie control module.

The invention discloses an electrical energy quality monitoring and evaluating system, which comprises a plurality of electrical energy monitors, a communication network, a plurality of enterprise service platforms and a government service platform, wherein the enterprise electrical energy monitors are connected to the enterprise service platforms through the communication network, and the independent electrical energy monitors and the enterprise service platforms are connected with the government service platform through the communication network; the enterprise service platforms are used for receiving basic electric power parameters acquired by the enterprise electrical energy monitors at monitoring points inside the enterprises, displaying the change conditions of the electric power parameters of enterprise distribution networks, and transmitting data to the government service platform at certain time intervals; and the government service platform is used for receiving the electric power parameters of the enterprise distribution networks transmitted by the enterprise service platforms and the parameters transmitted by the independent electrical energy monitors at the monitoring points in the regional distribution networks, and performing energy consumption audit, transient and stable electrical energy quality analysis, electrical energy quality level evaluation, harm extent evaluation and evaluation of providing the corresponding electrical energy quality improvement scheme and electrical energy quality improvement effect.

The invention provides a simulation modeling method for equivalent simulation of a doubly-fed wind-power generator set. A frequency converter of the doubly-fed wind-power generator set is simulated by controlled source. The simulation modeling method includes the following steps of (1), building a model of a circuit of the doubly-fed wind-power generator set; (2) building an equivalent model of the doubly-fed wind-power generator set; (3) building a grid-integration testing system of the doubly-fed wind-power generator set; and (4) setting up a testing system for multiple wind-power generator sets, wherein in the step (2), the equivalent model of the doubly-fed wind-power generator set is built on the basis of characteristics of a controlled voltage source of an alternating-current side and a controlled current source of a direct-current side of the frequency converter of the doubly-fed wind-power generator set. By the aid of the simulation modeling method, transient-state characteristics of the doubly-fed wind-power generator set can be simulated accurately, and different characteristics and mutual affection among multiple wind-power generator sets can be computed. High-frequency on and off of fully-controlled devices cannot be taken into consideration, and simulation efficiency is improved greatly. The more the wind-power generator sets are simulated, the more evidently the efficiency is improved, simulation step-length can be increased on the premise of guaranteeing accuracy, and simulation efficiency is improved greatly.

The invention relates to a virtual synchronous generator control method based on self-adapting moment inertia. The output of a grid-connected inverter in distributed generation is connected with an AC bus of a filter capacitor Cf which is in parallel connection with the grid-connected inverter through a filter inductor Lf; sampling is performed to obtain the output power, the voltage and the current of an output interface of an inverter; the output power, the voltage and the current are transmitted to a VSG (virtual synchronous generator) algorithm; the calculated terminal voltage of a VSG stator is sent to be controlled by a voltage external loop; the voltage external loop adopts a PI controller to stably load the voltage; the current of the filter capacitor is sent to be controlled by a voltage internal loop; the voltage internal loop adopts a PI controller to increase the response speed; a control signal is outputted by a voltage-current dual-closed loop to the grid-connected inverter; the moment inertia in the virtual synchronous generator in the control method can be changed in a self-adapted manner according to the change capacity of the system frequency. Through the adoption of the virtual synchronous generator control method disclosed by the invention, the transient state process of the system is reduced; a great deal of harmonic waves in the system is offset; the stability of frequency and the stability of voltage can be improved; the adaptability and the power supply quality of a micro-electrical network are improved; the problem that in a conventional method, the output frequency is reduced, is solved.

The invention discloses a distribution network single-phase ground fault route selection method based on a transitional quantity signal. The method comprises the following steps: determining the initial time of the fault; the adaptive selection of the characteristic frequency-band; and calculating and comparing the transient zero-sequence current-component amplitude value in the characteristic frequency-band; the invention definitely distinguish the fault line and the healthy line by using the characteristic that the abundant transient high-frequency component is include in the fault current at the moment of occurrence of the single-phase ground fault; and the method can adaptively determine the characteristic frequency-band and perform fault route selection by using the characteristic quantity of the transient zero-sequence current in the characteristic frequency-band, and the success ratio reaches above 99 percent through a great mount of simulation and the field data test, and is far higher than that of the route selection method in the prior art at present. The route selection method can be applied to the fault route selection for the transformer station where the neutral point is not grounded and is not directly grounded.

The invention provides a method for transient stability assessment and real-time control of an electric system. According to the method, technologies concerning knowledge discovery are introduced to realize the stability assessment and the control of the electric system; and on the basis of establishing a transient stability assessment model, the corresponding relation between the system running condition and the overall stability of the electric system is found out, the inherent running discipline of the electric system are grasped, and the fast assessment of the stable running state of the electric system is realized, therefore, the actual running management of the electric system can be guided. The method has the advantages that timely and effective stability control scheme can be established for the running state which loses stability after great disturbance, and the safe and the stable running of the system can be ensured at lowest price.

The invention belongs to an electric energy quality monitoring technology, particularly a ship electric energy quality monitoring system. The system comprises a data analysis evaluation subsystem and data acquisition processing subsystems distributed on each node. The data acquisition processing subsystems are used for acquiring three-phase voltage and current signals of a ship power grid in real time and providing the three-phase voltage and current signals for the data analysis evaluation subsystem by the Ethernet; the data analysis evaluation subsystem is used for completing calculation of steady-state electric energy quality indexes in an on-line mode and giving an electric energy quality comprehensive evaluation according to an index weight; the detection of transient-state electric energy quality perturbation parameters is completed in an off-time mode; the steady-state electric energy quality indexes comprise a voltage deviation, a frequency deviation, harmonic waves, three-phase unbalance, voltage fluctuation and flicker; and the transient-state electric energy quality perturbation parameters comprise short duration voltage variation, time varying harmonic waves and inter-harmonics. According to the system, all the nodes on the power grid can be simultaneously monitored, the factors influencing the electric energy quality can be analyzed by a plurality of indexes and the level of the electric energy quality of the power grid is timely known.

A software licensing method and system are in which a set of transient state information 154 for the target computational device at a selected point in time is used to generate a license key 144 to validate that the use of the licensed application is in accordance with the terms and conditions of a license.

The invention provides a cooperative control method and system of a battery energy storage power source participating in secondary frequency modulation of a power grid. The cooperative control method comprises the steps of: mounting the battery energy storage power source in a regional power grid needing the cooperation; obtaining an ACE (Area Control Error) signal from an electric grid control center by a cooperative control module; participating in the secondary frequency modulation of the power grid by the battery energy storage power source, and then dividing a typical application scene to determine the chance and participating degree of participation in the frequency modulation; converting a theoretical frequency modulation command into a practical frequency modulation command, then realizing charge / discharge control of the battery energy storage power source through an energy conversion system, and accordingly helping a traditional frequency modulation power source to finish a secondary frequency modulation process. The transient and steady performances of the secondary frequency modulation of the power grid are improved obviously, the frequent start of the traditional frequency modulation machine set is reduced, and balance between supply and demand of the power grid is maintained rapidly.

The invention provides a fault route-selecting method by using small current grounding system simulated by measured zero-mode current. The method includes following steps: when a generatrix zero-mode voltage instantaneous value is over the limit, a fault route-selecting is started and recorded immediately; zero-phase shift digital wave filter is used to obtain a high-frequency transient weight of each feed line zero-mode current; orderly the feed line is supposed to be fault feed line, the rest of the high-frequency transient weight of the feed line zero-mode current is quantificationally solved by using the measured simulative method according to the supposed high-frequency transient weight of the feed line zero-mode current and each feed line zero-order distributing capacitance parameter; the actual-measured wave shape and simulative wave shape of the high-frequency transient weight of the feed line zero-mode current are analyzed and a average relative coefficient of the actual-measured wave shape and simulative wave shape of the high-frequency transient weight of the feed line zero-mode current are solved, the route-selecting criterion is formed to achieve the fault route selection. The principle analysis and simulation indicate that route selection of this method is accurate and reliable.

The invention discloses a new method for performing fault line selection by using the characteristic of a non-power frequency transient state fault component for extracting single-phase fault zero-sequence current by using Hilbert-Huang transform (HHT). The method comprises the following steps: performing EMD decomposition on fault zero-sequence current of each feeder line by using the HHT to acquire an IMF component of the zero-sequence current of each feeder line; constructing a resolving signal according to Hilbert transform, solving instantaneous amplitude and frequency of the zero-sequence current of each feeder line, and eliminating a power frequency component in the instantaneous frequency of the zero-sequence current of each feeder line to acquire a non-power frequency fault component; and forming a line selection criterion according to the characteristics that the amplitude of the non-power frequency fault component of the fault line is greater than that of the non-fault line and the polarity of the fault line is opposite to that of the non-fault line. The line selection method is not affected by an arc suppression coil, and is applicable to non-grounded, arc suppression coil grounded and high-resistor grounded systems, overhead lines or cable lines and cable overhead mixed lines; and the line selection result shows that the method applied to low-current single-phase grounding fault line selection is accurate and reliable.