65 results about "Power systems protection" patented technology

A continuous grounding system for use in an alternating current system including a transformer is disclosed. The system includes a switch assembly connected between a transformer neutral of a transformer and a ground, the switch assembly having an open position and a closed position, the open position disrupting the path through the switch assembly between the electrical connection and the transformer neutral, and the closed position establishing a path connecting the electrical connection to the transformer neutral through the switch assembly, wherein in normal operation of the alternating current electrical device the switch assembly remains in a closed position. The system also includes a DC blocking component positioned in parallel with the switch assembly and connected between the transformer neutral and the ground. The system further includes a control circuit configured to control the switch assembly, the control circuit including a sensor configured to actuate the switch assembly to an open position upon detection of a predetermined harmonic signal threshold at one of the transformer phases or a predetermined threshold of DC current between the transformer neutral and ground.

The invention discloses a time synchronizer applied to protective test equipment of a power system. The time synchronizer is characterized in that the time synchronizer is provided with a wireless control host machine with a master clock time synchronization hardware module, wherein the wireless control host machine is directly connected with a software simulation platform of an upper computer, and a slave clock time synchronization hardware module is arranged in a protective test terminal. Time synchronization between the master and slave clock time synchronization hardware modules is implemented through a wireless communication application IEEE (Institute of Electrical and Electronic Engineers) 1588 time synchronization protocol. According to the technology provided by the invention, the wireless IEEE1588 time synchronization protocol is applied to a secondary side test protective device of a transformer substation of the power system, so that a network signal of a mutual inductor obtained by simulation is synchronously output in real time, in this way, a signal network output of the power system can be stimulated more authentically so as to test a plurality of secondary side test protective devices of the transformer substation at the same time.

The invention provides a high-voltage direct-current grounding electrode line high-resistance fault positioning method and belongs to the technical filed of power system protection and ranging. When grounding faults occur in a high-voltage direct-current grounding electrode, terminal voltage and current are measured by utilizing a normal line to calculate voltage to a electrode stop point, terminal voltage, current and fault boundary conditions are measured by utilizing a fault line to calculate voltage of the electrode stop point, a fault positioning function is written according to electrode stop point voltage equivalence, and fault distance is calculated by solving the fault positioning function. By the method, fault grounding electrode line fault ranging is achieved based on existing fault recording data, measurable single-end voltage and current are utilized, opposite-end data is unnecessary, high sampling rate is unnecessary, and filed implementation is easy.

A continuous grounding system for use in an alternating current system including a transformer is disclosed. The system includes a switch assembly connected between a transformer neutral of a transformer and a ground, the switch assembly having an open position and a closed position, the open position disrupting the path through the switch assembly between the electrical connection and the transformer neutral, and the closed position establishing a path connecting the electrical connection to the transformer neutral through the switch assembly, wherein in normal operation of the alternating current electrical device the switch assembly remains in a closed position. The system also includes a DC blocking component positioned in parallel with the switch assembly and connected between the transformer neutral and the ground. The system further includes a control circuit configured to control the switch assembly, the control circuit including a sensor configured to actuate the switch assembly to an open position upon detection of a predetermined harmonic signal threshold at one of the transformer phases or a predetermined threshold of DC current between the transformer neutral and ground.

An apparatus and method for protecting a power system comprising a generator providing power to an alternating current bus, a power converter for converting alternating current power on the alternating current bus to direct current power on a direct current bus, and a direct current load powered by the direct current power on the direct current bus. An undesired condition is identified at the input to the power converter from the alternating current bus. The undesired condition is caused by at least one of the power converter, the direct current bus, or the load. The power converter is disconnected from the alternating current bus in response to identifying the undesired condition for at least a time delay. The time delay is selected such that the power converter is disconnected from the alternating current bus before the alternating current bus is disconnected from the generator due to the undesired condition.

The invention provides an overvoltage suppression device of a three-phase frequency conversion AC power generation system. The device comprises a generator three-phase voltage sampling circuit, an effective value computing circuit, a comparison circuit, an excitation negative voltage stabilization circuit, a CPLD processing circuit, a DSP processing circuit, an IGBT driving circuit and an energy absorption power loop. The overvoltage suppression device is matched with a voltage regulator of a generator, after overvoltage is generated, a transient overvoltage suppression sends a voltage adjustment prohibition signal, the voltage regulator of the generator no longer provides a secondary excitation current for the generator, and electricity in the generator is converted only from remaining energy in an excitation coil of a master generator. The transient overvoltage suppression device absorbs electromechanical energy in a controllable manner, thereby effectively suppressing transient overvoltage in the power grid so as to prevent power system protection caused by overvoltage, and smoothly converting the power grid voltage from transient high voltage to stable voltage so as to make thepower grid safer, more reliable and robust.

The invention belongs to the field of power system protection and control and particularly relates to a current protection and threshold crossing risk monitoring method for an urban power grid including EV (electric vehicle) charge-discharge stations. Probability distribution of discharge powers of the EV charge-discharge stations is formed on basis of charge-discharge data information of the EV charge-discharge stations; short circuit current probability distribution of each current protector is calculated through Gram-Charlier series and a semi-invariant; a short circuit current threshold crossing severity index is calculated through a utility theory; current protection and threshold crossing risk indexes of the urban power grid including the EV charge-discharge stations are then calculated. According to the method, risk assessment is performed by a probabilistic power flow method on basis of the utility theory and a risk theory; normal current protection is effectively guaranteed for the urban power grid including EV charge-discharge stations, and the urban power grid can run safely and reliably.

The present invention relates to a method for current compensation of a protection system for protecting a zone in a power system, which zone comprises a number of transmission lines connected to power sources and a number of transmission lines connected to a number of loads where the power sources and the loads are arranged outside the zone and a number of current transformers (CT) arranged to the transmission lines, wherein the method comprises the steps of continuously measuring all the incoming currents (Iin) to the zone, continuously measuring all the outgoing currents (Iout) from the zone, continuously calculating the differential current (Id) according to Id=Iin−Iout, continuously calculating q=Iout / Iin, continuously comparing q with set values and continuously comparing Iout with a set value Set1. The invention is characterised by setting Iout=Iin=Icomp at the instant when q changes and Iout exceeds the value set1, which is an indication of the occurrence of a fault external to the protection zone due to saturation of the CT of the faulted outgoing transmission line, and using the value Icomp in the protection system in order to prevent tripping of the protection system. The present invention also relates to a device and a computer program product for performing the method.

The invention discloses an automatic cooling switch cabinet used for a fuse type isolation switch, belonging to the power system protection electric appliance technology field. The automatic cooling switch cabinet comprises a cabinet body, a fuse type isolation switch, a temperature-humidity detection unit, a control unit, an alarm unit and a fan. An air inlet and an air outlet are arranged on the cabinet; the fan is installed at the air inlet; the fuse type isolation switch is installed between the fan and the air inlet; the temperature-humidity detection unit is connected to the control unit for detecting temperature and humidity inside the cabinet body; and the output terminal of the control unit is connected to the alarm unit and the fan. With the air inlet and the air outlet being arranged on the switch cabinet, the automatic cooling switch cabinet performs real-time monitoring on the temperature inside the switch cabinet and starts up the fan to radiate heat when the temperature and the humidity are detected to be high, which solves the problem that the temperature inside the switch cabinet is too high, which affects the working of the fuse type isolation switch. Besides, the invention also has advantages of automatic heat radiation, autonomous detection, easy usage and low cost.

The present invention related to the field of power system protection and control, presents a voltage travelling wave differential protection method considering the influence of frequency-dependent parameters, which provides more accurate and rapid fault identification. The technical scheme of the present invention is as follows: a calculation method of voltage travelling-wave differential protection for VSC-HVDC transmission lines, taking the influence of the frequency-dependent parameters into consideration, the steps are as follows: calculating a characteristic impedance and propagation coefficient of the frequency-dependent transmission line in time domain, collecting voltage and current signals at the both ends of the transmission line and then calculating the forward and backward voltage travelling wave, respectively, comparing a differential value of voltage travelling wave with a preset threshold value to determine whether the internal fault occurs.The present invention is mainly applied in the field of power system protection and control.

The invention relates to a dual-output optical current transformer and a signal processing method thereof. The optical current transformer is characterized by comprising an LED (Light-Emitting Diode)light source; an optical current sensor, a first photodetector, a second photodetector, an AD (Analog-to-Digital) collection preprocessing circuit and a digital signal processing circuit, wherein theoptical current sensor is used for sensing current information of a detected conductor according to light emitted by the light source to obtain a first optical signal and a second optical signal; thefirst photodetector is used for detecting the first optical signal to obtain a first output signal; the second photodetector is used for detecting the second optical signal to obtain a second output signal; the AD collection preprocessing circuit is used for obtaining a first direct current component and a second direct current component; and the digital signal processing unit is used for converting the first direct current component information and the second direct current component information into a first feedback control digital quantity and a second feedback control digital quantity andfeeding the first feedback control digital quantity and thesecond feedback control digital quantity to the AD collection pre-processing circuit; after the AD collection pre-processing circuit obtains the output value, the digital signal processing unit demodulates the output value to obtain a current flowing through the detected conductor. The dual-output optical current transformer and the signal processing method thereof provided by the invention can be widely applied to the field of power system protection.

The invention designs a water-cooled power monitoring device with a transient monitoring capability. A functional panel is used for controlling, displaying and alarming an electric power monitoring device, displaying the on-off state and alarm information of the electric power system protection switch sent by a programmable logic controller, and outputting the on-off control information of the electric power system protection switch to an input andoutput module; a sensor module is used for measuring operation parameters of the power system; the programmable logic controller completes acquisition of operation state information of the power system protection switch and linkage protection information processing of the protection switch through the input and output module, exchanges information with a computer, and outputs a power system network topology structure and alarm information to the function panel. The water-cooled power monitoring device integrates the functions of real-time information monitoring, power supply and distribution network control, fault diagnosis, alarm, noise reduction and the like, realizes centralized management of a power system, and ensures stable and reliable operation of the power system.

The invention discloses a hybrid-power stepless speed changing system, which comprises an output shaft, a motor power coupling mechanism, a stepless speed changing mechanism and an input shaft. The input shaft is connected with an engine and used for transmitting power to the stepless speed changing mechanism. The motor power coupling mechanism comprises a motor stator, a motor rotor and a motor supporting shaft connected with the motor rotor and further comprises a synchronizer used for realizing power transmission between the input shaft and a motor supporting shaft and / or power transmissionbetween the motor supporting shaft and the output shaft. The hybrid-power stepless speed changing system has advantages that by arrangement of the synchronizer, operation under a pure engine drive mode can still be realized when high-voltage electricity exhausting or high-voltage power system protection occurs, and accordingly an application range of the hybrid power technique is greatly expanded.

The invention belongs to the technical field of power system protection control, and particularly relates to a parameter configuration method and a configuration tool for a transformer substation terminal interval. The method comprises the following steps: firstly, generating a template of a data structure, and then generating a corresponding data structure according to input actual configurationinformation and the template of the data structure so as to store the actual configuration information; generating a configuration file in an XML format according to the generated corresponding data structure; and finally, converting the generated configuration file in the XML format into a configuration file in a format required by configuration, and importing the finally generated configurationfile into the protection device. According to the invention, the configuration file in the format required by configuration can be flexibly and quickly generated according to the actual configurationinformation input by development and maintenance personnel, and the automatic configuration of the interval parameters of the transformer substation terminal is realized, so that the configuration requirements of different intervals can be met, the interval parameters can be flexibly configured, the configuration difficulty is reduced, and the configuration efficiency is improved.

The invention provides a microgrid distributed system protection method and device and relates to the technical field of power system protection. The method is applied to any stage of protection unitexcept a bus protection unit in microgrid distributed system protection equipment, and the protection equipment comprises multiple stages of protection units which are arranged according to voltage grading of a microgrid distributed system; the method comprises the following steps: detecting fault information in the microgrid distributed system, the fault information comprising island sign information; sending the fault information to an upper-level protection unit to enable the upper-level protection unit to generate a protection instruction according to the fault information; and receiving aprotection instruction, and executing a protection action according to the protection instruction. According to the invention, the microgrid protection equipment is subdivided into different levels of protection units with independent relative functions, each level of protection unit has detection, protection and control functions, and because the protection units are more independent and flexible, the equipment does not have a protection dead zone, and the protection reliability is improved.

The invention provides a distributed protection method with self-adaptive communication rate capability and a medium, which are applied to a power distribution system using an intelligent distributed feeder automation technology, and adjacent switches in a cable network line of the power distribution system perform remote communication by adopting a mobile communication technology. The distributed protection method comprises the following steps: when a switch in a control cable network line detects that a fault occurs in the line, if the line is in a normal communication delay, performing fault removal and isolation according to a quick-acting strategy, and if the communication delay is too high, automatically switching to a slow-acting strategy to perform fault isolation. According to the invention, fault positioning can be accurately realized and power system protection can be started.

The invention relates to a compression algorithm for black and white dot matrix data in a power system protection device, which comprises the following steps: S01, reading original dot matrix data ofone byte, judging whether the current byte is 0x00 or 0xFF, if not, copying the read original data to a compressed data writing position, and if so, carrying out the next step; S02, copying the read original data into the compressed data, and starting counting, wherein the counting number is the number of the continuous original data which is the same as the original data of the current byte; andS03, when bytes different from the bytes of the original data in the step S02 are read, returning to the step S01. The algorithm is good in actual engineering application effect, the data volume is averagely reduced by 35%, and the data volume of an individual interface can be reduced by 99%.

The invention relates to a high-resistance ground fault detection method based on zero-sequence current zero crossing point interruption discrimination and belongs to the field of protection and control of power systems. The method comprises the following steps of: acquiring a zero-sequence current instantaneous value of a monitored feeder line of a substation, calculating the time of the zero-sequence current less than a set value after the zero-sequence current is subjected to zero crossing, and determining that the zero crossing point interruption occurs and determining the fault to be a suspected high-resistance ground fault if the time exceeds a threshold; and determining that a steady-state high-resistance ground fault occurs if the duration of the suspected high-resistance ground fault exceeds the threshold. The method is applicable to a three-phase medium-voltage distribution system with neutral point grounded through resistance, and only a zero-sequence current signal is utilized; and compared with the conventional high-resistance ground fault detection methods, the method has high sensitivity.

The invention discloses a protection device outlet relay circuit impedance matching calculation method. The method comprises the steps that the input target voltage of an outlet relay circuit is calculated according to the input voltage range of the outlet relay circuit; according to the input target voltage, the action current of a relay and the resistance of a relay coil, the resistance of series resistors of the relay is calculated; the percentage of the resistance of the relay coil to the total resistance of the outlet relay circuit is calculated; and according to the percentage, the action voltage range of the relay is calculated. According to the invention, the reliable action voltage range of the relay is calculated according to the input voltage range of the outlet relay circuit and the percentage of the resistance of the relay coil; the voltage matches the rated resistance of the relay; and the reliability of a power system protection device is improved.

The invention relates to a power transmission line fault continuity judgment method based on image features, and belongs to the technical field of power system protection. Fault traveling wave data at the end of a power transmission line are collected, and a proper data window is selected based on linear calibration; displaying a proper data window in the image, and constructing a triangular bounding box which is well close to the region of interest; calculating the ratio of the continuation area formed by the fault traveling wave and the external tangent line in the bounding box to the whole bounding box, and judging whether a fault initial wave head exists or not according to the ratio; on the basis of existence of a fault initial wave head, regularization of initial and subsequent wave heads is carried out, relative characteristics of an arrival time sequence, a wave head amplitude and a slope are calculated based on the regularized calibration wave head, and finally fault continuity discrimination is realized. According to the method, the fault data without the traveling wave head can be automatically screened out, and the line fault traveling wave accessibility can be judged.

The present invention relates to the technical field of power system protection and fault detection, in particular to a method for modeling and analyzing arc-ground faults in distribution networks, which includes the following steps: Step 1. Establish a grounding variable resistance model of a fault branch, and the grounding can be The grounding variable resistance in the variable resistance model is the grounding resistance of the fault point on the fault branch; Step 2, establishes the short-gap breakdown arc model of the fault branch, and the short-gap breakdown arc model is the fault point on the fault branch The arc arc voltage; step 3, combining the grounding variable resistance model and the short gap breakdown arc model to establish a distribution network arc ground fault model based on the breakdown gap and variable resistance in different scenarios. The invention has the characteristics of obvious zero-break characteristic and accurate response to various types of grounding faults, provides sufficient theoretical support for the research and simulation of grounding faults in the subsequent lifting distribution network, and has strong practicability.

The invention relates to the technical field of electric power test devices, in particular to a short-circuit test device for three-phase current containing direct-current component. The device comprises a three-phase power supply input circuit, a three-phase synchronous signal circuit, an initial short-circuit angle adjusting circuit, a three-phase transformer, a three-phase transformer control circuit, a short-circuit characteristic time constant adjusting circuit and a short-circuit signal output circuit, wherein the three-phase power supply input circuit comprises a power supply main switch, a power supply indication element and an overcurrent protection element of the short-circuit test device, the three-phase synchronous signal circuit determines one of three phases A, B and C as a calculation initial short-circuit angle of a short-circuit output signal through a selection switch, and the initial short-circuit angle adjusting circuit determines the number of short-circuit angles through a selection switch. According to the invention, a composite signal of a three-phase short-circuit current with an additional nonlinear direct-current characteristic component and an adjustable short-circuit initial angle can be output, and verification of actual short-circuit effect simulation are provided for various protection devices in electric power system protection application.

The invention belongs to the technical field of power system protection and control, and in particular relates to a hybrid method for distributed grid-connected island detection. The method includes the following steps: collect the voltage value of the public coupling point of the distributed grid-connected power generation system; perform wavelet transformation on the collected voltage value, and calculate the average value of the absolute value of the wavelet coefficient within a voltage period, and calculate the average value As the input signal of the BP neural network, the BP neural network is used for pattern recognition; when it is determined that the distributed grid-connected power generation system has entered a suspected island state based on the output results of the BP neural network, it is detected whether the voltage of the grid-connected point has a set carrier superimposed on it. signal, when the set carrier signal is detected, it is determined that the distributed grid-connected power generation system has entered the island state. This method uses wavelet neural network combined with carrier communication technology to detect whether the distributed grid-connected power generation system enters an island state, improves the island recognition rate and the reliability of island detection, and has no detection blind spots.

The invention relates to the technical field of drilling, in particular to a continuous circulation type drilling power system protection device and a protection method thereof. The designed auxiliary positioning mechanism can accurately measure the displacement amount of the drill rod when the drill rod moves, the drill rod is convenient to position, install and replace, when the drill rod reaches a preset position, the gear can be driven to rotate to drive the auxiliary fixing sleeve to fix the drill rod, and the drill rod is convenient to install. The designed hydraulic system is provided with an adjusting valve, the sealing performance of the two sets of sealing clamping plates can be switched through the adjusting valve, and overhauling and later-period coping with various complex working conditions are facilitated. The designed hydraulic system is matched with the sealing mechanism, compared with a traditional sealing mechanism, active sealing of two sets of elastic sealing rings is achieved, the oil outlet pipe and the oil inlet pipe are adopted for conveying hydraulic oil, and the sealing performance and safety of the device are greatly improved.

The invention relates to a multifunctional power system protection device, which belongs to the field of power system protection equipment. The device can switch between flat ground and rough roads, the device can change the height, the device can dissipate heat, the device can prevent the system from being polluted by dust, and the device can Clean the filter screen, the device can prevent collision, the device can be easily disassembled, the device can peel the cable, the device can cut the cable, and the device can protect the cutting knife. The multi-functional mobile wheel mechanism is located under the protective shell mechanism. The multi-functional mobile wheel mechanism is used for the movement of the device. The protective shell mechanism is used for heat dissipation and storage of dust pollution. The anti-collision dust cleaning seat mechanism is welded on both sides of the protective shell mechanism. The connection mode between the cable peeling mechanism and the protective shell mechanism is welding, the connection mode between the cable cutting mechanism and the protective shell mechanism is welding, the anti-collision dust cleaning seat mechanism is used for dust removal, the cable peeling mechanism is used for cable peeling, and the cable cutoff Mechanism for cutting cables.

The invention discloses an unmanned aerial vehicle power system protection device which comprises a sliding sleeve, a sliding sheet, a buckle and a fixing rod. The buckle comprises a buckle head and abuckle groove which can be assembled and separated through insertion fit. The sliding sleeve is an arc-shaped hollow strip-shaped panel, one end is open, and the other end is closed; one end of the fixed rod is fixedly connected with the inner wall of the sliding sleeve, and the other end is fixedly connected with arms of the unmanned aerial vehicle; the sliding sheet is an arc-shaped strip-shaped sheet plate and is arranged in the sliding sleeve, and one end of the sliding sheet extends out of the opening end of the sliding sleeve and can freely slide relative to the sliding sleeve; the buckle groove is fixedly connected with the closed end of the sliding sleeve, and the buckle head is fixedly connected with the end, away from the closed end of the sliding sleeve, of the sliding sheet. The device can be arranged on each arm of the unmanned aerial vehicle to protect each propeller of the unmanned aerial vehicle, and the problem that blades of the unmanned aerial vehicle knock down branches to cause air crash is prevented.

The invention relates to the technical field of power system protection, in particular to an arc extinguishing circuit breaking device. The device comprises an installation shell, a static contact, a moving contact and an insulation arc extinguishing piece. The installation shell is provided with a first containing cavity formed in the first direction and a second containing cavity formed in the second direction and communicated with the first containing cavity. The static contact is arranged in the first accommodating cavity; the moving contact is movably arranged in the first accommodating cavity along the extension direction of the first accommodating cavity, the moving contact can be connected to the static contact or separated from the static contact to connect or disconnect a circuit, and the joint of the moving contact and the static contact directly faces the second accommodating cavity; the insulating part is movably arranged in the second containing cavity in the extending direction of the second containing cavity, and when the moving contact is separated from the static contact, the insulating part can move to the position between the moving contact and the static contact to isolate arc discharge. The moving contact and the static contact are protected from being oxidized, and good conductive characteristics are kept.

The invention provides a relay protection action behavior intelligent evaluation method and system. The method comprises the steps of acquiring and preprocessing fault event information; analyzing the preprocessed information data, and generating a data chain table; calling data in the data chain table for calculation to obtain the characteristic quantity of each required parameter; according to the characteristic quantity, in combination with the relay protection action condition, calling a pre-constructed expert rule module to carry out identification and judgment; identifying and judging events, analyzing and evaluating action behaviors of relay protection in the events according to identification and judgment results, pushing the events which cannot be automatically identified and judged to manual auditing, and updating and perfecting a knowledge base in an expert rule module for the events. According to the method, full coverage of analysis and evaluation of the protection action behaviors of the power system is realized, the protection action events do not need to be graded according to the influence degree, the requirements on knowledge and experience of auditing personnel are effectively reduced, and the processing pertinence and efficiency of field defects are improved.

The invention provides a line active power anomaly detection method not involving a phase angle. According to the method, pre-calibration or a reference mutual inductor with high precision is not needed, online detection can be achieved, and therefore the accuracy of protection setting and state estimation of the electric power system is guaranteed. Firstly, a line active loss model which does not involve a phase angle is deduced, and an active loss theoretical value during operation of a power transmission line can be determined; secondly, determining a PMU / SCADA positive sequence data measurement error limit and an operation parameter deviation limit of the line based on the accuracy grade of a line mutual inductor and the actual operation condition of the line; then, determining an active loss reasonable deviation value under a set data error limit and a line parameter deviation limit in combination with an error propagation law; and finally, comparing a difference value between an active loss measured value and a theoretical value, judging whether the difference value is within a reasonable deviation value, and outputting a line abnormal condition.

The invention relates to a power grid fault traveling wave fault location equation automatic construction method, and belongs to the technical field of power system protection. According to the invention, engineering processing is carried out on a grid method for power grid line fault wave process analysis; generating a total extension branch time record table and an extension branch record table based on a measuring point according to recursive data of a wave process grid method, and writing a wave propagation path equation in parallel; and on the basis of obtaining the traveling wave path equation expression, assigning unknown numbers and establishing an equation set in parallel, judging whether the linear equation set can be solved or not according to the relationship among the rank of the coefficient matrix, the number of equations and the number of the unknown numbers, if so, obtaining a corresponding distance measurement formula through symbolic operation, and if not, not forming the distance measurement formula.