52results about How to "Fast protection action" patented technology

The invention discloses a substation on-site protection system, which comprises single-interval protection, cross-interval protection, substation area protection and an automatic monitoring device, and is characterized in that on-site single-interval protection and a public acquisition control terminal are configured at lines, bus couplers and subsections; each side of a substation is configured with the on-site public acquisition control terminal; the cross-interval protection protects a host according to bus and transformer configuration; the substation area protection and the automatic monitoring device performs centralized screen forming configuration in a control room; and the system network is composed of a cross-interval protection private ring network, a monitoring ring network anda public ring network. The substation on-site protection system adopts the on-site single-interval protection, the distributed cross-interval protection and the bidirectional ring network, solves a problem that an intelligent substation relay protection system is reduced in rapidity and reliability and can adapt to various installation occasions and operation environments at the same time.

The invention provides an adaptive three-phase symmetric fault phase selecting method for an ultra high voltage (UHV) transmission line. The method comprises the following steps: adopting three-phase current on a fault circuit; calculating a zero-sequence current component, determining whether the zero-sequence current component exists or not, and respectively determining a threshold value Iset and a margin ratio Kset in three-phase symmetric fault phase selecting element criterion according to existence or not of the zero-sequence current component; calculating three-phase current break-variables delta IA, delta IB and delta IC; determining whether the amplitudes of the three-phase current break-variables are more than the set threshold value; and determining whether a ratio K between the maximum break-variable and the minimum break-variable in the calculated three-phase current is less than the definite value Kset of the set margin ratio or not. The method has reliable phase selection result and high action speed, can accurately and quickly select three-phase faults when convertible three-phase faults occur; and the provided three-phase symmetric fault phase selecting element is not affected by a transition resistor, and the transition resistor accelerates decay rate of a transient state component and ensures the break-variable to be reduced in asymmetric fault, thus being in favor of selection of three-phase fault.

The invention belongs to the technical field of power system relay protection, and discloses an electric transmission line fault detection method based on voltage traveling wave prediction. The method comprises the following steps of: firstly, acquiring voltage and current traveling wave components at the two ends of an electric transmission line at each sampling moment in real time, and performing phase-mode transformation to obtain 0, alpha and beta mode voltage and current traveling wave components on the two end sides of the electric transmission line at each sampling moment; secondly, computing a voltage traveling wave prediction component of an electric transmission line end at a moment t; thirdly, computing a three-phase voltage traveling wave prediction component at each sampling moment according to the prediction component; and lastly, subtracting the three-phase voltage traveling wave prediction component at the end of the electric transmission line acquired in real time respectively, obtaining an absolute value, and performing setting judgment according to the absolute value. According to the method, the voltage traveling wave component at each sampling moment is not required to be evaluated through interpolation operation, so that operand is reduced, a fault detection function can be completed in a short data window of a quarter of period, and protection action speed is high; and the method is suitable for performing traveling wave protection in the entire transient fault process of electric transmission lines of various voltage classes.

The invention relates to an action boundary based relay protection method for interphase faults of a self-adapting adjusting electric transmission line. The relay protection method comprises the following steps: measuring a fault interphase voltage, a fault interphase current and a fault interphase negative-sequence current at the relay location of the electric transmission line firstly; calculating an action boundary adjusting impedance, and calculating the sum of the action boundary adjusting impedance and a protection setting impedance to obtain the adjusted action boundary impedance; dividing the fault interphase voltage by the fault interphase current to obtain the measured impedance; judging whether the amplitude value of the measured impedance is less than that of the adjusted action boundary impedance or not; if yes, judging that the interphase short-circuit fault occurs within the protection setting range of the electric transmission line, and sending out an action trip signal. The relay protection method adopts a lumped parameter for modeling, is simple in algorithm principle and fast in protection action, can truly reflect the action boundary adjusting impedance affected by a transitional resistor and a load current, and adopts the action boundary adjusting impedance for real-time adjustment on the protection setting impedance, so that the protection action performance is prevented from being affected by the transitional resistor and the load current.

The invention relates to a grid line relay protection method applicable to double line faults. According to the method, when a grid topology structure changes after double line fault tripping occurs on a grid, a grid branch admittance matrix and a grid node incidence matrix do not need to be amended, and then the variable quantity of current flowing through each line after the grid double line fault tripping occurs can be calculated directly, so that the calculation time is short, the protection action speed is high and is higher than of a line backup protection algorithm based on the local amount decision, the line can be reliably locked before a line overload relay protection faulty operation, other faulty lines can be isolated rapidly in a tripping mode, and the operation safety and stability of the grid are improved.

The invention discloses a remote ultra-high voltage alternating-current transmission line fault determination method. The method comprises the steps that voltage and current travelling wave components at each sampling moment at protection installation positions at the two ends of an ultra-high voltage alternating-current transmission line are collected at first, the influence of line losses is calculated, the travelling wave electrical quantity at each sampling moment is utilized for calculating the current travelling wave component at one end of the ultra-high voltage alternating-current transmission line through a prediction algorithm, then a distributed capacitance current along the ultra-high voltage alternating-current transmission line is used as a braking current, the vector sum of the current travelling wave component, obtained through calculation, at one end of the ultra-high voltage alternating-current transmission line and the current travelling wave component, obtained through sampling, at the end of the ultra-high voltage alternating-current transmission line is used as a difference current, and phase splitting is carried out to form main protection of the ultra-high voltage alternating-current transmission line. According to the remote ultra-high voltage alternating-current transmission line fault determination method, the current travelling wave components at each sampling moment does not need to be solved through interpolation operation, the operand of current travelling wave protection is reduced, the movement speed of current travelling wave differential protection is improved, and the remote ultra-high voltage alternating-current transmission line fault determination method is applicable to ultra-high voltage alternating-current transmission line replay protection under different operating environments and circuit parameters.

The invention relates to a power transmission line phase-to-phase distance protection section III protection method. The method comprises the steps that a fault phase-to-phase voltage, a fault phase-to-phase current and a fault phase-to-phase negative-sequence current at a power transmission line protective installation position are measured firstly, a phase-to-phase arc voltage at a phase-to-phase short-circuit fault point of the power transmission line is calculated, and then the amplitude of the phase-to-phase arc voltage and a rated voltage amplitude of the power transmission line are utilized to form a power transmission line phase-to-phase short-circuit fault relay protection criterion. According to the power transmission line phase-to-phase distance protection section III protection method, lumped parameters are adopted for modeling, the algorithm principle is simple, programs are implemented easily, the calculation amount is small, and protective action is high in speed. By means of the power transmission line phase-to-phase distance protection section III protection method, the power transmission line phase-to-phase short-circuit fault relay protection criterion is formed by utilizing the amplitude characteristics of the phase-to-phase arc voltage, motion performance is not affected by transition resistance and load current, large-area power outage of a power grid caused by great shift of power grid tidal current due to phase-to-phase distance protection III protection false operations under the condition of overload of the power transmission line is effectively prevented, and operation safety and stability of the power grid are reinforced.

The invention discloses an adaptively-adjusted action boundary based single phase grounding fault relay protection method for power transmission line. According to the method, a fault phase voltage, a fault phase current, a fault phase negative sequence current and a zero sequence current in the protection installation position of the power transmission line are measured firstly; action boundary adjustment impedance is calculated; the summation of the action boundary adjustment impedance and protection set impedance is calculated to obtain adjusted action boundary impedance; measurement impedance is obtained by dividing the zero sequence compensation current by the fault phase voltage; then whether the measurement impedance amplitude is lower than the adjusted motion boundary impendence amplitude or not is determined; and if the measurement impedance amplitude is lower than the adjusted motion boundary impendence amplitude, a single phase grounding fault occurring in the protection set range of the power transmission line is determined, and a protection apparatus sends out an action tripping signal. The method adopts lumped parameters for modeling, so that simple algorithm principle, easy implementation of the programs, low calculated amount and high protection action speed are realized; the protection set impedance is adjusted in real time by the action boundary impedance, so that the protection action performance is not affected by the transition resistance and the load current; and therefore, the method can carry out correct and reliable action when the power transmission line is in the singe phase high resistance grounding fault.

A 220KV transformer dead-zone fault removal method that can prevent the fault from being removed for a long time and damage the transformer. The technical solution is: analyze the fault characteristics; state; or other protection trip outlets, the relay is in action; 2) The current of phase A or B or C on the side of the transformer is greater than the set value, or the zero-sequence current or negative-sequence current is greater than the set value; when the above two conditions are all met , exit the transformer differential protection TA on this side of the transformer after a delay, that is, the current on this side of the transformer does not participate in the calculation of the differential protection current of the transformer; TA, that is, the current on this side of the transformer participates in the calculation of the transformer differential protection current.

The invention discloses a grid circuit overload maloperation-preventing relay protection method based on wide-area information. According to the method, an existing wide-area measuring system of a grid is used for synchronously measuring the phasor quantity of the voltages and the phasor quantity of the currents of all transformer substations at first; if a grid single circuit trips, a wide-area backup protection system sequentially calculates the corrected impedance, the corrected admittance and the compensation voltage; voltages of all nodes of the grid of which the circuit has not tripped and the compensation voltage are superposed to obtain the voltage phasor quantities of all transformer substations of the grid which tripped; the currents flowing through all circuits in the grid are calculated and combined with circuit currents measured by the existing wide-area measuring system to form overload maloperation-preventing protection criteria. According to the grid circuit overload maloperation-preventing relay protection method based on the wide-area information, the protection action speed is high, the circuits can be reliably shut before ciruit overload protection maloperation occurs, other circuits are protected against overload and mistaken cutting, wherein the overload is caused by transferring of the currents after the grid single circuit tripped, and the large-area power failure of the grid is effectively prevented.

The present invention relates to the technical field of electric power system relay protection. Disclosed is a current traveling wave prediction-based method for electric power transmission line differential protection. The method: first, voltages and current traveling wave components of two ends of an electric power transmission line at sampling moments are collected; the voltages and current traveling wave components of the first 1 / 4 cycle moments of the sampling moments are utilized to predict the current traveling wave components of the two ends of the electric power transmission line at the sampling moments; respectively at the two ends of the electric power transmission line, a current traveling wave differential protection is constituted from the current traveling wave components of the sampling moments acquired via prediction and the current traveling wave components of the moments acquired via sampling by means of utilizing conventional proportional braking characteristics; if any one current traveling wave differential protection phase of the current traveling wave differential protection at the two ends of the electric power transmission line is activated, then protecting by transmitting a trip signal to circuit breakers at the two ends of the phase of the transmission line. The method of the present invention utilizes the voltages and current traveling wave components at the first 1 / 4 cycle moments of the sampling moments to predict and acquire the current traveling wave components of the electric power transmission line at the sampling moments, obviates the need for an interpolation operation to arrive at the current traveling wave components of the sampling moments, reduces the amount of traveling wave protection computation, is capable of completing a traveling wave fault protection function within a short data window of 1 / 4 cycle, is rapid in activating the protection, and is applicable in the traveling wave protection during the entire process of a transient fault of electric power transmission lines of various voltage levels.

The invention proposes a method and device for judging the direction of a high-resistance fault on a transmission line, collecting a discrete value sequence of a power frequency cycle of the zero-sequence current and three-phase voltage at the protection installation site as an input; Use the full-wave Fourier transform to calculate the phase angle of the power frequency components of each sequence, and use the phase angle difference between the zero-sequence current and phase voltage to select the faulty phase; use the zero-sequence current-phase voltage curve in the first The algebraic sum of the area enclosed by the quadrant and the instantaneous value of the phase voltage within a positive half cycle of the zero-sequence current determines whether the high-resistance fault is in the positive direction or the reverse direction. The invention can be directly applied to the protection device of the transmission line without installing new equipment, and has low cost, small calculation amount and fast response speed.

The invention discloses a method and system for identifying faults between grounding and phase-to-phase of a microgrid, which collects the sampling current value and sampling voltage value of the measured point, and calculates the power frequency mutation value of negative sequence power, the power frequency mutation value of negative sequence voltage, and the power frequency mutation value of negative sequence voltage. Negative sequence current power frequency mutation value; collect the real-time load current and real-time load voltage value of the measured point, and calculate the negative sequence power floating threshold, negative sequence voltage floating threshold, and negative sequence current floating threshold; according to the negative sequence power working The frequency mutation value, negative sequence voltage power frequency mutation value, negative sequence current power frequency mutation value and negative sequence power floating threshold value, negative sequence voltage floating threshold value, and negative sequence current floating threshold value are compared one by one to determine the fault point ; This method improves the reliability of the protection action and the speed of the protection action of the microgrid.

The invention discloses a current-transformer-saturation-influence-resistant traveling-wave differential protection method for currents of a lossy line. The method is characterized in that voltage and current traveling-wave components of transformer station protection mounting positions at two ends of the power transmission line are acquired at various sampling moments at first, influence of line loss is taken into consideration, each current traveling-wave component of one end of the power transmission line is computed by a prediction algorithm, and the computed current traveling-wave components and the sampled current traveling-wave components at the end of the power transmission line form traveling-wave differential protection criteria for currents. The current-transformer-saturation-influence-resistant traveling-wave differential protection method has the advantages that the current traveling-wave components at the various sampling moments are not required to be solved by means of interpolation operation, the calculation of the algorithm is reduced, and the protection action speed is increased; a traveling-wave protection function can be completed for a fault of the line within a quarter-period short data window by the method, the protection action speed is high, the influence of the line loss is taken into consideration, and accordingly the method is applicable to performing traveling-wave protection on power transmission lines in various voltage grades in integral transient fault procedures.

The invention discloses a fault detection and isolation method applicable to a multi-branch low-voltage direct-current power distribution system, and belongs to the safety detection technical field of a direct-current power distribution system. According to the method, single-branch sub modules are flexibly configured according to nodes and branches of the direct-current system; the multi-branch low-voltage direct-current power distribution system protection is formed comprehensively; fault recognition is realized by detecting the inductive current and the capacitor voltage characteristics in each branch sub module; and fault isolation is carried out by controllable electronic switches in the branch sub modules. According to the method, a direct-current circuit breaker is not required, so that the cost is relatively low; the fault detection and isolation method is applicable to the multi-branch and single-loop, single-pole and dual-pole direct-current power distribution system; the fault detection and isolation method is simple in method, high in protection action speed, and relatively high in transitional resistance tolerance; and meanwhile, only the fault branches are isolated, so that the power failure range is not enlarged.

The invention discloses a line phase-to-phase fault double-end protection method based on phase-to-phase arc light voltage characteristics. Fault phase-to-phase voltages and fault phase-to-phase currents of two ends of a power transmission line are measured first, the fault phase-to-phase voltage of the other end of the power transmission line is calculated by using the fault phase-to-phase voltage and the fault phase-to-phase current of one end of the power transmission line, a power transmission line phase-to-phase arc light voltage is figured out, and then the power transmission line phase-to-phase arc light voltage and a power transmission line rated voltage are utilized to constitute a phase-to-phase high resistance short-circuit fault voltage protection criterion of the power transmission line. In the method, influences of the power transmission line phase-to-phase arc light voltage are taken into consideration in an algorithm model, influences of transition resistance and load currents are eliminated in principle, great capacity for resisting to influences of transition resistance and load currents is achieved, and the method is suitable for relay protection of the whole fault process after a power transmission line phase-to-phase high resistance short-circuit fault occurs. Lumped parameter modeling is adopted in the method, the algorithm principle is simple, the program is easy to implement, the operation amount of algorithm is less, and the protection action speed is high.

The invention discloses a false synchronization differential protection sampling data rollback method and device of a half-wavelength power transmission line. The false synchronization differential protection sampling data rollback method comprises the steps of comparing passage delay time Tx with a power frequency period T; performing false synchronization differential impedance calculation on acurrent sampling point of sampling data rolled back to (Tx-T) moment of a side and a received sampling point of an opposite side if Tx is larger than T; performing false synchronization differential impedance calculation on the current sampling point of the side and the received sampling point of data rolled back to (T-Tx) moment of the opposite side if Tx is smaller than T; and unnecessarily performing rollback on the data if Tx is equal to T. By the false synchronization differential protection sampling data rollback method, the problem of longitudinal passage delay of false synchronizationdifferential protection in the half-wavelength power transmission line is solved in an emphasized way, false synchronization differential impedance protection calculation can be enabled to be performed by newest electrical quantity, and the protection action speed is increased.