179results about How to "Improve protection reliability" patented technology

A protection method may prevent a load-mismatch-induced failure in solid-state power amplifiers. In an RF power amplifier, the load voltage standing-wave ratio results in very high voltage peaks at the collector of the final stage and may eventually lead to permanent failure of the power transistor due to avalanche breakdown. The method avoids breakdown by attenuating the input power to the final stage during overvoltage conditions, thus limiting the output collector swing. This is accomplished by a feedback control system, which detects the peak voltage at the output collector node and clamps its value to a given threshold by varying the circuit gain. Indeed, the control loop is unlocked in the nominal condition and it acts when an output mismatching condition is detected. A control circuit also allows a supply-independent collector-clamping threshold to be accurately set.

The invention relates to a load fault diagnosis detection method and a device thereof. Rise phase current waveform sampling is driven through a load, comparison with a preset threshold is carried out, logic overturn of a diagnosis signal which exceeds the threshold occurs, a time of a logic overturn moment of the diagnosis signal is detected, the time and a preset benchmark value are contrasted and analyzed, hereby whether the load has short circuit, circuit break and load over-limit faults is determined, and simultaneously, whether the short circuit fault is short circuit to ground or short circuit to a power supply can be determined; through measuring time of drive starting moment and ending moment of diagnosis signal overturn, comparison with a driving signal is carried out, and hereby whether pulse width output of the driving signal has abnormity or not is determined. According to the method, only a diagnosis circuit is added based on a load performer driving circuit, additional cost is low, protection and control reliability in a load performer driving process can be raised substantially, and a foundation for load driving analysis and fault diagnosis is established.

A synchronization method for current differential protection comprises: selecting a point on the transmission line protected by the current differential protection; measuring the current and the voltage of each of the terminals of said transmission line; calculating the compensating voltage at the selected point respectively according to the measured current and the voltage of the each terminal; detecting and calculating the synchronization error by comparing all the compensating voltages.

A small current neutral grounding fault location method based on the direction of transient state reactive power is characterized in that change of voltage or current serves as a failure starting condition, and after the starting, the zero sequence voltage is taken as the participating voltage if a detection point can be used for detecting the zero sequence voltage and if not, the following steps are performed: 1, confirming the fault phase as per characteristics of three transient state line voltages, and 2, confirming the transient state line voltage including the fault message as per the type of the fault phase, taking the transient state line voltage as the participating voltage, confirming the characteristic frequency range, and further building a digital filter to filter the participating voltage and the zero sequence current signal, so as to obtain the component within the characteristic frequency range; and then confirming the direction of the reactive power of all the detection points through utilizing the components of participating voltage and the zero sequence current within the characteristic frequency range, so as to further confirm the fault section. According to the invention, the transient voltage and current signals as well as zero sequence voltage and line voltage are utilized at the same time, the positioning reliability is higher, the adaptability is stronger, quick direction protection for ground fault of all the voltage classes is applicable at the same time, and the protection speed and reliability are taken into consideration.

The invention provides a circuit current differential protection method preventing an abnormal large number of a combination unit. Firstly, the point with the maximum amplitude is selected by comparing cycle current sampling values on the two sides of a circuit, if the point is larger than an abnormal threshold, the differential motion does not act, if the point is not larger than the abnormal threshold, and the point with the second largest amplitude is selected on the same side with the maximum point; secondly, the current sampling value at the maximum point position and the current sampling value at the second largest point position are respectively modified according to logic, and complete cycle Fourier transform is carried out to obtain current phase magnitudes at the two ends; lastly, current differential protection judgment is constructed to achieve failure judgment. According to the circuit current differential protection method, the differential protection false action caused by the abnormal large number of the combination unit of an intelligent substation can be effectively prevented by processing the large number of the sampling values, and the circuit protection reliability is improved.

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 relates to a common-tower double-circuit line vertical fault zero sequence pilot protection error operation prevention method. The method comprises steps that zero sequence criteria are constructed and comprise main zero sequence direction criteria and zero sequence current start criteria; negative sequence criteria are constructed and comprise negative sequence direction auxiliary criteria, negative sequence compensation voltage start criteria, negative sequence current start criteria and a negative sequence voltage threshold; if the zero sequence criteria and the negative sequence criteria are simultaneously satisfied, a fault is determined to be a positive direction fault; if the zero sequence criteria are satisfied, the negative sequence current start criteria are not satisfied, and the negative sequence voltage threshold is satisfied, and the fault is determined to be an internal fault of an outgoing wire of a weak power source and is further a positive direction fault; if two ends of the line are determined to have positive direction faults, an internal ground fault of the line is generated, and a protection outlet is tripped. The method is advantaged in that through introducing negative sequence components and improving a compensation voltage, a zero sequence pilot protection error operation problem of a healthy line during generation of the common-tower double-circuit line vertical fault can be effectively prevented.

The invention belongs to the field of hydraulic engineering and rolling stone prevention and control engineering and relates to a tunnel portal flexible nose-shaped rolling stone discharging and guiding shed tunnel structure and a designing method thereof. The structure comprises multiple lambdoidal prevention and control individuals which are arranged along a slope, every two adjacent prevention and control individuals are in stacked-tile socketed connection or seamless sequential connection, each prevention and control individual comprises two truss structure ceilings which are mounted on a slope energy-consuming damping anchoring base through a supporting structure, and a composite energy-consuming cover plate covers each truss structure ceiling. The designing method aims to determine integral structural size and spatial position of a discharging and guiding shed tunnel and thickness of an energy-consuming damping material of a bearing platform. The tunnel portal flexible nose-shaped rolling stone discharging and guiding shed tunnel structure is simple in structure, unitary in component, standard in size, conducive to factory-scale production and quality control, beneficial to transporting and mounting in alpine canyon areas and good for subsequent maintenance due to modularized structure.

The invention discloses a method for processing boundary information deficiency of a centralization protector of a digitalized converting station, which comprises the following steps that: the centralization protector collects current and voltage values of the whole converting station and the states of circuit breakers, and acquires voltage and current sampling value information of the whole converting station in real time; when faults happen, if the current sampling value information of one line is deficient, a current sampling value of the information deficient line is synthesized on the premise that a bus is supposed to have no faults, and then a bus voltage and a line current sampling value are used, wherein the information deficient line adopts a resultant current, and the faults are removed through conventional line protection; and if the faults are detected on a first section of the conventional protection of the information deficient line, the circuit breaker of the line is tripped off without delay, and then the conventional bus differential protection is used for detecting whether the bus has the faults or not so as to determine whether to trip off all the circuit breakers connected with the bus. The method can quickly position the faults and remove the faults of boundary regions, greatly simplifies the cooperating setting of protection, and improves the reliability of the protection.

A single-phase grounding protective method of the fault current component phase ratio type generator's stator, belongs to electric technique field. The method is as follows: adopt half in quadrature wavelet as start tool; collect the zero sequence voltage component at generator terminal and neutral point side as reference electric quantity, the voltage transformer's wiring form adopt standard wiring; the modulus maximum's judging through the wavelet analyzing by which the zero sequence voltage including fundamental wave zero sequence voltage and thrice harmonic zero sequence voltage, is taken as start criterion; according to whether the phase angle ratio of the thrice harmonic voltage increment at the terminal and neutral point side meet the request, judge the whither the generator takes place single phase grounding fault at the interior of stator.

The invention relates to a protection starting method for an interface between a large-scale energy storage power station and a power grid, in particular to a large-scale battery storage power station interface protection method based on single-ended break variable of current. According to the method provided by the invention, the single-ended break variable of current is utilized to provide protection for the large-scale battery storage power station interface, only the single-ended current and voltage information quantities are needed; and the problems that the distributed power supply which is tied in grids through an inverter is low in reliability and sensitiveness while using the conventional three-section current protection and current sequence component are solved; under various fault conditions, the fault can be reliably detected, the simulation result shows that the method has higher protective sensitiveness and reliability, and the fault can be removed by reliable actions in two-phase short circuit, two-phase grounded short circuit and three-phase short circuit outside the grid.

The invention relates to a distribution network single-phase ground protection method based on zero-sequence current sudden change straight line fitting direction, belonging to the technical field of power system relay protection. For a resonant earthed system, when single-phase earth fault occurs on one feed line, firstly, a bus zero-sequence voltage in a short time window and zero-sequence currents of feed lines after the fault are intercepted and subjected to wavelet decomposition, and respectively extracted wavelet coefficients of a frequency band in which a power frequency is located; then the extracted wavelet coefficients are subjected to primary straight line fitting by using a least square method, and slope values of primary straight lines are solved; finally, the primary straight line slope value corresponding to the bus zero-sequence voltage is respectively multiplied by the primary straight line slope values corresponding to the feed line zero-sequence voltages; when the product is less than zero to determine positive-direction fault occurs on the feed line, a protective element acts; when the product is larger than zero to determine reverse-direction fault occurs on the feed line, and the protective element does not act. The distribution network single-phase ground protection method is low in using difficulty and high in protection reliability.

The invention provides a transient voltage suppressor and a fabrication method thereof. The transient voltage suppressor comprises a P-type substrate, an N-type epitaxial layer, a first groove, a second groove, a first P-type diffusion region, a second P-type diffusion region, P-type epitaxial layers, an N-type injection region and a P-type injection region, wherein the N-type epitaxial layer is formed on the P-type substrate, the first groove and the second groove are formed in a surface of the N-type epitaxial layer, the first P-type diffusion region is formed on a surface of the first groove, the second P-type diffusion region is formed on a surface of the second groove, the P-type epitaxial layers are formed in the first groove and the second groove and on the N-type epitaxial layer, the N-type injection region penetrates through the P-type epitaxial layer and extends to the N-type epitaxial layer between the first groove and the second groove, and the P-type injection region is formed on a surface of the N-type injection region.

The invention discloses transmission line self-adaptive single-end transient protection based on transition resistance and fault angle reductions. When the transmission line is in short circuit, a large amount of high-frequency signals produced by a fault are transmitted to two ends of the transmission line; and owing to affect of earth distributed capacitance of a bus, the high-frequency signals are obviously reduced via the bus, high-frequency component close to the fault side of the bus is invariably higher than that of the fault side of the bus, and the transition resistances and fault angles have a great affect on the high-frequency component produced by the fault. Relative reduction formulas and parameters are selected according to the type of the fault, the transient amount reduction is performed corresponding to the transition resistances and the fault angles, and protective criterion is constructed according to the reduction transient amount. According to the principle, fault feature amount with both directional elements and number comparing functions are constructed on the basis of the transient amount difference of reduction of two sides of the bus to determine a zone the fault occurs in. By the aid of the scheme, the affect to the single-end transient protection by the transition resistances and fault angle is eliminated to a maximum extent. Fault feature differences between the forward direction and reverse direction and inner zone and external zone are obvious, reliability and flexibility are high, the overall length of a line can be protected, protecting areas are twice that of traditional protecting areas, and requirements for the distributed capacitance of the bus are low.

The invention relates to a high-resistance grounding protection method for high voltage circuit, which belongs to relay protection field. The method is: the wavelet function is used as analysis tool; the mother line triphase voltage, circuit triphase current and zero series voltage and current are used as reference quantity of electricity, the connection way between the voltage mutual inductor and the current mutual inductor uses standard connection; the mold maximal value of triphase current and zero series current after wavelet analysis is used as starting device by means of 'or'; the mold maximal value of the line current or zero series current after wavelet analysis is used as starting element; the mold maximal value of the triphase other line voltage is used as the rule of interference resisting; finds out the grounding failure phase according to if the mold maximal value character is consistent or not; the zero series current and the voltage polarity are used as direction judgment accordance. The invention can judge if there has single-phase high-resistance grounding failure in the electric line, it has direction performance, and uses the mother line voltage as interference resisting accordance, it has a high protection sensitivity and reliability.

The invention discloses a current increment protection method capable of reflecting a mean current change rate. The method comprises the following steps of: sampling feeder line current by an isolation amplification unit to obtain an instantaneous current value by using a metro DC feeder line protection device; filtering a high frequency component by using a digital filtering algorithm, and calculating an actual current value; when current increment in a sampled data window exceeds a set starting value, starting protection, and stating performing timing by using an exit timer; calculating a current change rate in a time period from 20ms before the protection is started to 20ms after the protection is started, and if the current change rate exceeds a set value, and is kept for longer than 20ms, arranging an increment protection enable flag; and when the time of the exit timer exceeds a set increment protection time value, and the current increment is not lower than a set increment protection returning value, and is provided with the increment protection enable flag, protecting an exit to be tripped. By the method, the mean current change rate in the time period is reflected, and is stable, reliable and not fluctuated along with the fluctuation of current change rates.

An electronic protection device for protecting at least one electrical load, connectable to the protection device, whereby the electronic protection device has an input terminal and an output terminal, and whereby the protection device includes a fuse element, which is thermally self-resetting, and whereby the fuse element is provided and set up to conduct or limit a first current as a function of a fuse element temperature, whereby a limiting component is provided to limit the first current, and whereby the limiting component has a first transistor that is connected in series to the fuse element and a monitoring circuit that influences the first transistor. The monitoring circuit blocks the first transistor when the first current reaches or exceeds a predefined maximum current value and unblocks it when the first current reaches or falls below a predefined reset current value.

The invention relates to a lightning protection method by grounding the nearest point of a signal feeder port, which comprises a nearest grounding point of the signal feeder port, a down lead, an insulating material and a metal grounding plate, wherein one end of the down lead is connected with the nearest grounding point of the signal feeder port, the other end is connected with a grounding body, a housing of a system device is isolated with the ground by using the insulating material, a layer of the metal grounding plate is laid below the insulating material, the metal plate is connected with the grounding body, and the sizes of the metal plate and the insulating material are at least larger than the contactable human-machine distance. The lightning protection method has the benefits of eliminating a bleeder dissipation current channel formed by lightning potential introduced from a power supply and a signal interface through the housing at the lower part of a machine device and the ground, leading the ground potential of the housing at the lower part of the device to suspend by leading the housing at the lower part of the device to be insulated and isolated with the ground, eliminating the probability of leading the external lightning potential to form lightning current and pass through in the system device, leading the place within a certain range below the system device to form the isopotential surface through the metal plate by utilizing the metal plate laid below the insulating plate and further ensuring the personal safety of staff walking on the system device. The method has high protection reliability and maintenance-free property and can simultaneously effectively reduce the mounting cost and the construction cost of the system.

In an N-channel type field effect transistor constituting an input / output protection circuit, an N-type well 1a with a lower dopant concentration than the source region 3c is formed under the source region 3c.

The invention discloses an Ethernet-based current differential protection device and an implementation method thereof, wherein the device comprises a clock module, an acquisition module, an Ethernet communication interface module, a data receiving module, a data sending module, a synchronous module and a differential calculation module; the clock module is connected with the acquisition module through a line; the acquisition module is respectively connected with the synchronous module and the data sending module through lines; the data sending module is connected with the Ethernet communication interface module through a line; the Ethernet communication interface module is connected with the data receiving module through a line; the data receiving module is connected with the synchronous module through a line; the synchronous module is connected with the differential calculation module through a line; and the Ethernet communication interface module is in bidirectional connection with the Ethernet through a line. The differential protection device is connected with the Ethernet, and sending and receiving of sampling data between differential protections are realized by using IEC61850-9-2 standard; and the device has the characteristics of enlarging the application range of differential protection and reducing the investment cost for realizing communication service.

The invention discloses a silicon carbide activation annealing method. The method comprises the following steps: forming a first protection layer on the surface, subjected to ion implantation, of oneside of a silicon carbide wafer; forming a second protective layer on the surface of one side, at which the first protective layer is formed, of the silicon carbide wafer; carrying out annealing treatment of the silicon carbide wafer with the second protection layer, wherein the thermal stability of the second protection layer is superior to that of the first protection layer during annealing treatment. A first protection layer and a second protection layer are formed on the surface of silicon carbide. During the annealing treatment of the silicon carbide wafer, the second protection layer canprevent the first protection layer from melting at a high temperature and prevents the sublimation of silicon atoms, and the first protection layer can effectively prevent silicon atoms on the surface of the silicon carbide wafer from sublimating and depositing again, so the problems of sublimation and deposition of silicon atoms on the surface of silicon carbide in the annealing process can be solved through the two protection layers, and the reliability of activating annealing protection of silicon carbide is improved.

The present invention discloses a method for protecting a data service in Metropolitan Area Transport Networks, a work path for services transport is established between a source node and a work destination node of the services in the Metropolitan Area Transport Network, and the method includes: setting a protection destination node using the nodes except the work destination node, and establishing a protection path between the source node and the protection destination node to protect the services of the work path; detecting by the source node the failure state of the links of the work path and the protection path, and the failure state of the nodes in the links; detecting by the work destination node and the protection destination node the failure state of the links connecting themselves with data devices, respectively, and notifying the source node when there is the failure state; switching the data services of the work path to the protection path after the source node detects the failure state of the link of the work path or the failure state of the nodes in the link, or receives a failure state notice from the work destination node.

The invention discloses a phase current sudden change based earth fault protection method which comprises the following steps: 1) online monitoring the zero sequence voltage of a power distribution network wherein when the zero sequence voltage exceeds the limit value of the voltage, the transient phase current signals of all lines are collected; 2) extracting the sudden changes in the transient phase current signals of all lines; 3) conducting two-on-two correlation analysis on the sudden changes in the transient phase current signals to obtain phase correlation coefficients [Rho AB, Rho BC Rho CA]; comparing for the smallest correlation coefficient Rho min; and 4) based on the identical correlation coefficients to find out the lines in fault. The method, with simple principles, is easy to perform for enhanced protection accuracy and reliability.

The invention discloses a method for compensating capacitance current in differential current of a generator. The winding capacity of a generator is equivalent to a generator terminal and a neutral point of the generator, but the winding capacity is not partitioned into two equal parts and the partitioning coefficient is calculated according to the structure of the generator. The method can be used to compensate the capacitance current in differential current so as to improve the protection reliability; meanwhile, the method is easy to operate and can prevent the protection false operation and failure action.

The invention discloses a noncontact charging open circuit protection device, which comprises a noncontact power emission unit (1), a noncontact power transmission unit (2) and a noncontact power receiving unit (3), wherein a first control unit and a second control unit carry out information interaction in real time through wireless communication; the second control unit monitors open circuit voltage V and current A of the noncontact power receiving unit (3) in real time; the second control unit detects that the current A changes, and feeds information back to the first control through the wireless communication; a comparison control unit compares load voltage V+ with reference voltage of the noncontact power receiving unit (3) in real time; when an open circuit fault occurs in a load of the noncontact power receiving unit (3), output of a comparator controls a relay Kp to be closed; and the first control unit controls the output of an inverter to achieve a protection function.

The invention provides a transient voltage suppressor which includes a P type substrate and an N type epitaxial layer. The N type epitaxial layer comprises a first part and a second part. The transient voltage suppressor also comprises a first P type doping area formed at the surface of a first part, a second P type doping area formed at the surface of a second part, and a P type epitaxial layer formed on the N type epitaxial layer, the first P type doping area and the second P type doping area. A first diode is formed by the P type substrate and the first part, a second diode is formed by the P type substrate and the second part, a third diode connected to the first diode is formed by the first part and the first P type doping area, a fourth diode connected to the second diode is formed by the second part and the second P type doping area, the negative electrode of the first diode is connected to the negative electrode of the second diode, and the negative electrode of the third diode is connected to the negative electrode of the fourth diode.

The invention provides a transient voltage inhibitor and a manufacturing method thereof. The transient voltage inhibitor includes a P type substrate, an N type epitaxial layer formed on the P type substrate, a first P type polysilicon, a second P type polysilicon, a first groove, a second groove, a first N type doped region formed on the inner surface of the first groove, a second N type doped region formed on the inner surface of the second groove, a third P type polysilicon formed on the surface of the first N type doped region in the first groove, and a fourth P type polysilicon formed on the surface of the second N type doped region in the second groove, wherein the first P type polysilicon and the second P type polysilicon penetrate through the N type epitaxial layer and extend to theP type substrate; the first groove and the second groove are formed on the surface, far away from the P type substrate, of the N type epitaxial layer; and the third P type polysilicon is also connected with the fourth P type polysilicon. The transient voltage inhibitor has the advantages of small device area, low process difficulty, low manufacturing cost, and higher protection performance and reliability.

Provided in the present invention are a network element and a protection method for ring network protection, the method comprising: upon the detection of a fault in a neighboring link, determining one or more faulty ring networks; performing protection switching on the faulty ring networks; encapsulating the ring network identifiers of the faulty ring networks in a protocol message; sending the protocol message to neighboring network elements on the faulty ring networks so that the network elements on the faulty ring networks can receive the protocol message and determine the faulty ring networks. The network identifier is an identifier owned by each ring network and used for differentiating from other ring networks; and the protocol message is used for indicating the network elements on the faulty ring networks to perform protection switching. The embodiment of the present invention provides the network element and the method for ring network protection, service logic separation and differentiated service among multiple rings on a single link are realized through the ring network identifiers, and nodes on the ring networks are coordinated to compete the protection switching of the ring networks, so as to improve the reliability of ring network protection.

A transient voltage suppressor comprises a P-type substrate, a first N-type doping layer formed on the P-type substrate, a P-type epitaxial layer formed on the first N-type doping layer, an N-type epitaxial layer formed on the P-type epitaxial layer, a second N-type doping layer formed on the N-type epitaxial layer, a first groove and a second groove passing through the second N-type doping layer,the N-type epitaxial layer and the P-type epitaxial layer and extending to the first N-type doping layer, silicon oxide layers formed on the side walls of the first groove and the second groove, anda metal layer formed in the first groove and the second groove and on the second N-type doping layer, wherein the metal layer comprises a first part formed in the first groove and connected with the first N-type doping layer, a second part formed in the second groove and connected with the first N-type doping layer and a third part adjacent to the second N-type doping layer between the first groove and the second groove.