53results 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 discloses a current differential protecting method of a wind electricity direct current microgrid under direct current bipolar short circuit failure. When a differential current is larger than a set value, it is judged that the failure occurs, breakers at the two ends of an electric transmission line under protection are controlled to be switched off, and meanwhile an absorption circuit is switched on. By means of the method, the faulty line can be switched off rapidly in a millisecond, and a fault current is prevented from reaching an overcurrent value on account of low impedance of a system at a fast speed, so that the whole system is prevented from breakdown. When the current differential protection loses efficacy, under voltage protection serves as a second defensive line, the circuit and power electronic components such as a diode are prevented from being damaged by a large short circuit current, and the safe operation of the system is guaranteed.

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 relates to a phase difference principle based power distribution network differential protection method. Current and voltage signals at each load switch are acquired; a phase difference of currents corresponding to two adjacent load switches is calculated, wherein at least one of the two adjacent load switches meets a condition that delta I phi max>n.delta IT+delta Idz; and if the phase difference of the currents corresponding to certain two adjacent load switches is greater than a set threshold value, then a section between the two adjacent load switches is a fault section, and the two adjacent load switches are tripped off. According to the method, only the phase difference of the currents at the two adjacent load switches needs to be calculated; fault determination is realized according to the condition met by the phase difference; the method has low requirement on data synchronization; the fault determination can be performed according to acquired information; the time required for the whole determination process is very short; the protection action speed is high; and the problem of low action speed in an existing relay protection method for a power distribution network is solved.

The invention discloses a lossy electric transmission line current traveling-wave differential protection method. The method comprises the following steps: collecting voltage and current traveling wave component of protection mounting parts at two ends of an electric transmission line at each sampling moment, and taking the line loss influence into consideration; calculating the current traveling wave component of one end of the electric transmission line through a forecasting algorithm, and forming current traveling wave differential protection according to the obtained current traveling wave component and the sampled traveling wave component of the line at the end, if differential protection for traveling wave of any phase current initiates, sending trip signals to circuit breakers at two ends of the line of the phase. According to the method, the interpolation operation is not needed to get the current traveling wave component at each sampling moment, so as to reduce current traveling wave protection calculation amount, and improve current traveling wave differential protection action speed; the electric transmission line current traveling wave protection function can be finished in a short data window with one-fourth period; the protection action speed is fast; and the line loss influence is taken into consideration. Therefore, the method is suitable for the traveling wave protection of a whole breakdown transient process of lossy transmission lines at various voltage levels.

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 method for transformer excitation surge current latching. Compared with the conventional latching method, the second harmonic single-phase latching principle is adopted, the method solves the problem that the latching time is too long when the regional external fault of an air-drop fault transformer is converted into a regional internal fault of heterogeneous phase in the conventional latching scheme and the problem that the fault cannot be quickly cut off, the speed of protection action is greatly improved, and safe operation of the transformer is ensured; meanwhile, under the condition that the protection is in normal surge current, latching protection can be reliably performed, and error operation of current differential protection is prevented; and the implementation of the method does not raise higher requirement for the conventional protective platform, the implementation threshold is low, and the method is convenient for popularization and use.

The invention discloses a method and a system of substation area zero sequence current protection. The method and the system of the substation area zero sequence current protection comprise the following steps: obtaining zero sequence current protection action information of opposite terminal transformer substation protection by utilizing the existing redundant channel of pilot protection, integrating the zero sequence current protection action information of the opposite terminal transformer substation protection with zero sequence current protection action information of a home station, conducting decision fusion to make sure the position of a fault element, and forming a tripping decision of the substation area zero sequence current protection. The method and the system of the substation area zero sequence current protection improve overall performance of the traditional zero sequence current protection, guarantee selectivity of the zero sequence current protection, and accelerate the speed of a protective action.

The invention provides a method and a system for protecting double ends of a direct-current transmission line with an increased opposite-end current break variable. The method and the system determinethe current difference value and the current break variable of a line by collecting the current of the direct-current transmission line, start direct-current protection when the current difference value of the line meets a protection starting criterion, determine whether the preset opposite-end current break variable boost criterion is established or not according to the current difference valueof the line and the current break variable, and finally determine whether the direct-current protection action is output or not according to the determination result. The method and the system for protecting the direct-current transmission line with increased opposite-end current break variable can greatly improve the protection action speed of the whole-line metallic fault, the whole-line high-resistance fault, the tail-end high-resistance fault and the metallic fault in the direct-current transmission line region, and can better improve the protection performance of the direct-current transmission line.

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 present invention relates to a reverse bias test sample protection method and device. The method provides a plurality of samples to be tested, a gate bias voltage circuit and a reverse bias voltage circuit. The device further comprises a fuse group and a low-voltage relay group, the fuse group comprises protection fuses having the same quantity as the samples to be tested, the low-voltage relay group comprises low-voltage relays having the same quantity as the samples to be tested, the first end of each sample to be tested is electrically connected with the gate bias voltage circuit, the second end of each sample to be tested is connected with the first end of a corresponding protection fuse in the fuse group and the first end of a normally open contact of a corresponding low-voltage relay in the low-voltage relay set, the second end of each fuse is electrically connected with the reverse bias voltage circuit, the second end of the normally open contact of each low-voltage relay isconnected with one end of the normally open contact of a high-voltage relay KM0, and the other end of the normally open contact of the high-voltage relay KM0 is earthed. The protection trigger current can be flexibly set to improve the response speed and protection accuracy of the protection motion.

The invention discloses a method for protecting a power grid wide-area relay based on unit output power and load change influence. Firstly, a power grid existing wide area measurement system is used for synchronously measuring the voltages and currents of all transformer substations of a power grid to acquire power grid synchronous data. The incidence matrix between the currents of all circuits of the power grid is calculated through a wide area backup protection system, and the incidence matrix between the currents of all the circuits of the power grid and node injection currents is calculated. When a power grid topological structure is changed after a power grid dual-circuit fault and tripping occur, the admittance matrix of power grid branch circuits and the incidence matrix of power grid nodes do not need to be calculated again, the variation of the transient currents of other circuits of the power grid are calculated directly through power grid parameters before a dual-circuit fault, calculation time is short, and the protection movement speed is high and is higher than that of an existing circuit backup protection algorithm based on local quantity decisions.

The invention discloses a current-transformer-saturation-influence-resistant traveling-wave differential protection method for currents of a non-loss line. The method is characterized in that voltage and current traveling-wave components of two ends of the power transmission line are acquired at various sampling moments at first, a current traveling-wave component of one end of the power transmission line at a current sampling moment is computed by the aid of the voltage traveling-wave component at the previous quarter-period moment, and the computed current traveling-wave component of the end of the power transmission line and the sampled current traveling-wave components of the end of the line form traveling-wave differential protection criteria for the 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 an algorithm is reduced, and the protection action speed is increased; the method can complete a traveling-wave protection function for a fault of the power transmission line within a quarter-period short data window, and the protection action speed is high.

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.

Disclosed is high-voltage direct current transmission line single-ended quick acting main protection method. The high-voltage direct current transmission line single-ended quick acting main protectionmethod mainly comprises the steps of A, collecting the outlet current ia(t) of a rectifier and the outlet current ib(t) of a direct current filter; B, performing wavelet decomposition and recomposition on rectified current of the latest 300 hours to obtain a subhigh-frequency-band-rectified wavelet decomposed current sum; C, performing wavelet decomposition and recomposition on filter current ofthe latest 300 hours to obtain a subhigh-frequency-band-filtered wavelet decomposed current sum; D, calculating the difference D(t) between the subhigh-frequency-band-rectified wavelet decomposed current sum and subhigh-frequency-band-filtered wavelet decomposed current sum to obtain the mean subhigh-frequency-band current difference of the latest 100 hours; E, if the mean subhigh-frequency-band current difference is higher than a set value D<set>, performing line main protection action, else, performing no action. The high-voltage direct current transmission line single-ended quick acting main protection method can be higher and more accurate in main protection action.

The invention discloses a microgrid grounding and interphase fault identification method and system. The microgrid grounding and interphase fault identification method comprises the steps of acquiringa sampling current value and a sampling voltage value of a tested point, and calculating a power frequency break variable value of a negative sequence power, a power frequency break variable value ofa negative sequence voltage and a power frequency break variable value of a negative sequence current; acquiring a real-time load current and a real-time load voltage value of the tested point, and calculating a negative sequence power floating threshold value, a negative sequence voltage floating threshold value and a negative sequence current floating threshold value; and judging a fault pointaccording to a result of comparing the power frequency break variable value of the negative sequence power, the power frequency break variable value of the negative sequence voltage and the power frequency break variable value of the negative sequence current with the negative sequence power floating threshold value, the negative sequence voltage floating threshold value and the negative sequencecurrent floating threshold value in one-to-one correspondence. By the method, the protection action reliability is improved, and the microgrid protection action speed is increased.

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.

Disclosed is a 220kv transformer dead-zone fault removing method. The fault removing method can prevent relatively long fault removing time, and can prevent damage to the transformer. According to the technical scheme, the fault removing method comprises the steps that fault characteristics are analyzed; and judging criteria are proposed according to the fault characteristics: 1) when a backup protection tripping outlet on the transformer side exists, a relay is in an action state; or other protection tripping outlet exists, the relay is in an action state; and 2) the A phase, or B phase or C phase current on the transformer side is greater than a setting value, or a zero-sequence current or a negative-sequence current is greater than the setting value; when the above two conditions are fully satisfied, the transformer differential protection TA on the transformer side is quitted after a certain time delay; namely, the current on the transformer side does not participate in the transformer differential protection current calculation; when any one of the two conditions is not satisfied, the transformer differential protection TA on the transformer side is connected immediately by zero second; and namely, the current on the transformer side participates in the transformer differential protection current calculation.

The invention discloses a method for rapidly removing an internal outlet fault of a controllable high-voltage reactor for line protection. The method comprises the steps that: the current of a side circuit breaker, the current of an intermediate circuit breaker, the current of the head end of a controllable high-voltage reactor and the voltage of a line are collected in real time, and a differential current and a braking current are calculated; after protection is started, if split-phase current differential protection does not act but local side distance I section protection acts, whether there is an internal outlet fault in the controllable high-voltage reactor or not is judged according to a fault current, a fault voltage and the head end current of the controllable high-voltage reactor; and if it is judged that the internal outlet fault of the controllable high-voltage reactor occurs on the local side and the action time of the distance I section is less than a threshold, the differential current and the braking current do not compensate the head end current of the controllable high-voltage reactor on the local side any more, split-phase current differential protection quickly acts after meeting the condition, and circuit breakers on the two sides are tripped off. When the internal outlet of the controllable high-voltage reactor has a fault, if the distance section I acts, the split-phase current differential protection on the two sides quickly acts. The fault clearing time is less than 0.1 s, and the stability requirement of the system can be met.

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 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.

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.