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626results about How to "Prevent misoperation" patented technology

Spare power automatic switching device and method for three-segment bus two-segment switch

A three-busbar two-section switch standby self-casting apparatus, belonging to power distribution field, includes two power supply lead-in circuit breakers, three busbar segments and two section breakers. Two standby self-casting devices being mounted on the position of the two section breakers; the standby self-casting device being equipped with a current detection loop, a voltage detection loop and a control circuit; the current detection loop using the signal of a two-path lead-in current transformer as ''non stream'' criterion, and using the current signal of the corresponding section breaker as ''over current'' criterion; while the voltage detection loop using the voltage signals of the two busbar segments, neighboring the corresponding section breaker, as ''pressure/non-pressure'' criterion. The standby power supply self-casting device includes a electrification discrimination circuit, a first and a second startup condition judgment circuit, a standby self-casting motion circuit and a rear acceleration motion circuit. The invention also discloses standby self-casting method for the apparatus. The apparatus implements power supply rapid automatic switching when the lead-in is failure under different running modes of the three-section busbar, and ensures the power supply reliability under accidents status.
Owner:BAOWU CHARCOAL MATERIAL TECH CO LTD

Thunder-lightening induced solid-phase arc-extinguishing lightning arrester

The invention discloses a thunder-lightening induced solid-phase arc-extinguishing lightning arrester. The thunder-lightening induced solid-phase arc-extinguishing lightning arrester mainly consists of a lightning arrester shell, an arc-extinguishing rotary table, an electric conduction metal plate, a starting rod, a clamping rod, an induction coil, an arc-extinguishing barrel and a counting pointer; the arc-extinguishing rotary table is arranged inside the lightning arrester shell, and a flat spiral spring for pushing the arc-extinguishing rotary table to rotate is arranged at the central position of the arc-extinguishing rotary table; the electric conduction metal plate is arranged at the upper part of the arc-extinguishing rotary table; the arc-extinguishing rotary table is provided with a plurality of arc-extinguishing gas pills in the peripheral direction; one side of each arc-extinguishing gas pill is provided with a trigger electrode and a groove respectively, one end of each trigger electrode is connected with one of trigger ends of the corresponding arc-extinguishing gas pill through a lead, and the other ends of the trigger electrodes extend out of the edge of the arc-extinguishing rotary table; and the other of the trigger ends of the corresponding arc-extinguishing gas pill is connected with the electric conduction metal plate through a lead. The thunder-lightening induced solid-phase arc-extinguishing lightning arrester is simple in structure, reasonable in design, high in arc-extinguishing ability and stable and reliable to work, and the arc-extinguishing gas pills are changed quickly and conveniently.
Owner:王巨丰 +1

Method for positioning short-circuit fault of distribution network based on distributed intelligent multi-calibration

The invention relates to a method for positioning a short-circuit fault of a distribution network based on distributed intelligent multi-calibration. The method comprises the following steps of: arranging a plurality of intelligent agents in the distribution network and establishing a modeled multilevel multi-verification short-circuit fault positioning rule for different operating modes of the distribution network; in the operation process of the distribution network, monitoring operation information of a local current distribution network in real time through each distributed intelligent agent; once the current is out of limit, sending a current out-of-limit signal to the directly-adjacent intelligent agent and a superior intelligent agent and checking whether a short-circuit fault early-warning signal exists locally; if so, assuring that the short-circuit fault happens locally; otherwise, waiting for receiving the current out-of-limit signal sent by the directly-adjacent intelligent agent; and after delaying the signal for time t, according to the local current out-of-limit signal and the received current out-of-limit signal, carrying out rule matching and multi-condition calibration to determine a fault diagnosis result by utilizing a local short-circuit fault positioning rule library and combining a wiring type of the distribution network and the position of the intelligent agent.
Owner:STATE GRID SHANGHAI ENERGY INTERCONNECTION RES INST CO LTD

Adaptive cascade direction interlocking relaying method based on GOOSE (Generic Object Oriented Substation Event)

ActiveCN103022993ANarrow down the outageEasy to interoperateEmergency protective circuit arrangementsProtective relaySelf adaptive
The invention relates to an adaptive cascade direction interlocking relaying method based on GOOSE (Generic Object Oriented Substation Event), which comprises the following steps: 1) initial interlocking directions of protective relays are set according to an initial interlocking direction tuning rule; 2) a directional element judges the direction of a current fault current which is compared with the initial interlocking directions by a direction comparator to judge whether the directions of two parts are the same, if yes, the step 3) is carried out, if not, IN2 is gated, and a interlocking signal is output to OUT2; 3) the direction comparator gates IN1, and outputs the interlocking signal to the OUT1 and the direction of the output signal is opposite from the initial interlocking direction at this time; 4) a receiving virtual terminal judges whether the interlocking signal is received, if yes, the interlocking is carried, if not, the step 5) is carried out; and 5) an over-current element judges whether the current fault current exceeds a local over-current protection starting fixed value, if yes, a trip signal is sent. In comparison with the prior art, the method has the advantages that the safe and reliable operation of a system is ensured and applicability is good.
Owner:SHANGHAI JIAO TONG UNIV +1

Exciting current emulation calculating method and device at time of direct-current magnetic biasing

ActiveCN102545156AIdentify the harmonic characteristics of excitation currentIdentifying Harmonic CharacteristicsEmergency protective circuit arrangementsExcitation currentElectric network
The invention provides an exciting current emulation calculating method at the time of direct-current magnetic biasing. The calculating method comprises the steps of: constructing an electric network model according to a target electric network; building a transformer magnetizing current curve according to the transformer no-load excitation characteristic curve; setting direct-current magnetic biasing exciting current I0, and revising the transformer magnetizing current curve; after setting other node and shunt parameters of the electric network, carrying out emulation operation; and obtaining steady-state exciting current according to the emulation data, calculating the direct-current component I'0, revising the transformer magnetizing current curve again until I'0=I0, when I'0=I0, comparing I2 and KxbI1, and carrying out inrush current locking operation when |I2| is larger than kxb * |I1|. According to the invention, emulation calculation can be rapidly carried out on the transformer exciting current at the time of set direct-current magnetic biasing, the harmonic wave characteristics of the transformer exciting current can be effectively identified, and the influence of the exciting current at the time of direct-current magnetic biasing on the transformer protection is analyzed, thus the phenomenon that the protection element fails to operate or has unwanted operation is prevented and favorable influence is brought for the power transmission and transformation system.
Owner:CHINA ELECTRIC POWER RES INST +1

Anti-interference electricity protecting method and anti-interference electricity protecting apparatus for electric equipment

The invention relates to an anti-interference electricity protecting method and an anti-interference electricity protecting apparatus for a motor or electric equipment under an interference electricity state of a grid. The method comprises a step of judging and identifying an interference electricity fault of the grid, which is the step for a process of judging the timeout of the over-current locking under-voltage, as well as a step of charging the protecting device; and the method can transmit an interference electricity recovering restarting signal depending on a set value of the delayed starting time. The anti-interference electricity protecting apparatus comprises a hardware module which is used for implementing an anti-interference electricity protecting function and an interference electricity state judging logic function module which is used for identifying an interference electricity fault of the grid. According to the technical scheme of the grid interference electricity identifying, the over-current locking under-voltage judgment, the under-voltage timeout locking judgment and the voltage recovery judgment are adopted, to effectively distinguish the grid fault from a motor short circuit accident, a grid interference electricity fault and a grid power-loss accident as well as other faults or accident events differing in property and type, thereby avoiding error action events of the protecting device in case of the motor short circuit accident and the grid power-loss accident, and guaranteeing the equipment and the personnel security.
Owner:BAOWU CHARCOAL MATERIAL TECH CO LTD

Method for judging lock by zero sequence voltage and current

The invention discloses a method for judging lock by zero sequence voltage and current, relating to a line protection method. In the existing line protection, in particular in weakly electrically and strongly magnetically connected double circuits, a mutual inductance electric potential is easy to cause longitudinal zero sequence direction protection misoperation. The technical scheme of the method disclosed by the invention comprises the following steps of: (1) sampling voltage and current wave forms of a mutual inductor by a line protecting device, and figuring out the sizes of zero sequence voltage and zero sequence current of a fundamental wave; and (2) when the line protecting device judges that a power grid is abnormal and zero sequence power flows from a line to a bus, allowing an element in a zero sequence direction to operate if the zero sequence voltage is larger than a zero sequence voltage threshold value and the zero sequence current is larger than a zero sequence current threshold value; otherwise, locking the elements in the zero sequence direction. Zero sequence current locking and zero sequence voltage locking conditions are added to protection in a longitudinal zero sequence direction, thus non-fault line longitudinal zero sequence direction protection misoperation caused by zero sequence mutual inductance can be prevented, and the reliability of longitudinal zero sequence direction protection in the weakly electrically and strongly magnetically connected double circuits is improved.
Owner:STATE GRID ZHEJIANG ELECTRIC POWER +1

Checking method and device for correctness of virtual terminator association configuration of intelligent substation

The invention relates to a checking method and device for correctness of virtual terminator association configuration of an intelligent substation. The method comprises the steps that primary equipment and the topological relation of the intelligent substation are obtained according to an SSD file of the intelligent substation; the secondary function configuration, corresponding to the primary equipment, of secondary equipment is obtained according to the SSD file; the logic connection relation between secondary functions of the secondary equipment of the intelligent substation is obtained according to the primary equipment, the topological relation and the secondary function configuration corresponding to the primary equipment; correctness of virtual terminator two-end IED / LD / LN association configuration in the logic connection relation is checked according to a preset rule. Secondary virtual circuit logic connection errors caused by virtual association configuration errors can be rapidly and effectively checked, maloperation caused by the virtual terminator association configuration errors is avoided, risk of misoperation of running equipment is reduced in the reorganization, expansion and debugging process of the intelligent substation, and safe production and reliable operation of the intelligent substation are ensured.
Owner:POWER DISPATCHING CONTROL CENT OF GUANGDONG POWER GRID CO LTD +1

Fault locking method for relay protection in digital substation

The invention relates to a fault locking method for relay protection in a digital substation. In the relay protection, a plurality of IED (Intelligent Electronic Device) distributed fault detection elements are integrated with various fault identification criterions to effectively identify faults of a power system; a protection device and intelligent unit double-fault locking mechanism is adopted, wherein a process layer communication CPU (Central Processing Unit) on the protection device only releases GOOSE (Generic Object Oriented Substation Event) trip locking and forwards a GOOSE trip signal to an intelligent unit on the premise that a trip command for protecting the CPU and a fault detection FD open command exist simultaneously; and the intelligent unit only releases locking and trips on the premise that the GOOSE trip command and the FD open command are received simultaneously. On the basis of network information sharing, the fault locking method provided by the invention is integrated with various fault identification criterions to effectively identify the fault of the power system by adopting the plurality of the IED detection elements, and prevents false tripping caused by IED abnormality so as to improve the reliability of the power system.
Owner:XJ ELECTRIC +2

Judgement procedure for digital transformer differential protection to prevent TA secondary circuit failure from leading to mistaken operation

The invention discloses a method for preventing differential protection misoperation of a digital transformer caused by such errors as short circuit, open circuit and etc. on the secondary circuit of a current transformer. Criterions for the errors in the TA secondary circuit are as follows: when a digital transformer protection device is running normally (a primary system accessed by the transformer does not go out of order), if the TA secondary circuit error is determined as that one- or two-phase current drops by 30 percent or higher, and difference current exists, then, the TA secondary circuit is determined as being out of order. On the premise of sudden current change: the current after the sudden change drops rather than increases, and the primary system has errors, or at least one-phase current will increase; therefore, one- or two-phase current of three-phase current drops by 30 percent or higher at the side; meanwhile, the three-phase current at other sides does not vary. If the conditions are met, the TA secondary circuit is determined as being out of order; after the TA secondary circuit goes out of order, an alarm signal is launched, and a latched or an unlatched difference protection outlet can be selected.
Owner:BEIJING SIFANG JIBAO AUTOMATION +1

Automatic switching transport network self-healing recovery method based on break before make

ActiveCN102904632ASolve the problem that the self-healing of the optical fiber differential protection service cannot be realizedRealize intelligent self-healing functionFault recovery arrangementsFiberRecovery method
The invention relates to an automatic switching transport network self-healing recovery method based on break before make, which is characterized in that an original service is firstly broken, a new service path is then established, and the transmitting and receiving of the line protection service are guaranteed to be in same route at any time; the self-healing recovery method concretely comprises two processes of service self-healing when the failure of a line fiber differential protection channel occurs, and service recovery when the failure of an original communication network is corrected; (1) when the failure of the line fiber differential protection channel occurs, the service self-healing process is as follows: a dynamic recovery channel based on control plane is arranged in the line fiber differential protection channel, the channel based on break before make is formed, the blocking state is opened, the channel time delay is recalculated, the operational parameters of a device are adjusted, and the self-healing process is finished; and (2) when the failure of an original communication network is corrected, the service recovery process is as follows: the ASON (automatic switch optical network) fault is corrected, the service reroute is broken to recover the channel, a line protection device monitors a channel fault, the ASON reestablishes the original designed route channel, and the service recovery is realized. The automatic switching transport network self-healing recovery method based on break before make realizes that the transmitting and receiving of the fiber differential protection channel are carried out in the same route at any time, the time delay during transmitting and receiving is maintained the same, and the automatic switching transport network self-healing recovery method based on break before make is applicable to the power line fiber differential protection service.
Owner:CHINA SOUTHERN POWER GRID COMPANY +1

Adaptive-slope transformer zero-sequence differential protection method and device

The invention discloses an adaptive-slope transformer zero-sequence differential protection method comprising the following steps: the zero-sequence current at the output end of a Y winding side of a transformer and the grounding zero-sequence current at a neutral point side of the transformer are compared to calculate the zero-sequence differential current and the brake current of the transformer; the size and direction of obtained zero-sequence power are calculated based on the zero-sequence voltage and the zero-sequence current at the output end of the Y winding side of the transformer, and the zero-sequence differential braking slope of the transformer is dynamically adjusted; when an external fault occurs, dynamically adjusted high slope is adopted in zero-sequence differential protection to prevent external metallic grounding and prevent transformer zero-sequence differential protection malfunction caused by CT saturation of the grounding zero-sequence current at the neutral point side; and when an internal fault occurs, low slope is adopted in zero-sequence differential protection. The invention further provides a corresponding device. The method and the device are used to monitor to-ground insulation of a power transformer in real time. An external grounding fault and an internal grounding fault of a transformer can be distinguished quickly and accurately. High sensitivity to internal faults is realized. Reliable braking can be achieved with use of high slope for an external fault.
Owner:NR ELECTRIC CO LTD +1

Bus protection method for quick locking in CT (current transformer) asymmetric wire breakage

The invention discloses a bus protection method for quick locking in CT (current transformer) asymmetric wire breakage. The bus protection method comprises the following steps of: calculating the electrical quantities of a differential current, a brake current, the sudden-change current of each branch, a zero-sequence current and the like; judging that the CT wire breakage occurs according to a criterion that the differential current increases while the brake current is unchanged, and starting differential protection if the CT wire breakage does not occur; selecting a suspected CT wire breakage branch according to whether a current exits in the branch of each circuit, and starting differential protection if the suspected CT wire breakage branch is not selected; and confirming the CT wire breakage according to information of the sudden-change currents and the zero-sequence currents of other branches except for the suspected CT wire breakage branch, and starting differential protection if the CT wire breakage cannot be determined. The protection method disclosed by the invention is capable of preventing the mistaken action of bus differential protection in case of CT asymmetric wire breakage and no high short-circuit current, and ensuring the correct action of bus differential protection regardless of whether the CT asymmetric wire breakage occurs in case of a high short-circuit current.
Owner:NANHUA UNIV

Modular multilevel converter bridge arm short circuit fault protection method

The invention relates to fault protection methods of converters, specifically to a modular multilevel converter bridge arm short circuit fault protection method. The method comprises the following steps of 1) setting a fault detection time gap [delta]t of modular multilevel converter bridge arm parallel protection switches; 2) setting a fault motion threshold value Q; 3) setting voltage threshold values Ulim.ac and Ulim.arm; 4) detecting voltage to ground Uac(t) of the alternating-current end of a modular multilevel converter and computing Q1=abs(aveage(Uac([delta]t)))-Ulim.ac; 5) detecting bridge arm voltage Uarm(t) of the modular multilevel converter and computing Q2= abs(aveage(Uarm([delta]t)))-Ulim.arm; 6) determining that a bridge arm short circuit fault occurs if Q2 x Q 1 > Q; and 7) trigging the bridge arm parallel protection switch of a sound phase when it is determined that the modular multilevel converter has the bridge arm short circuit fault. According to the invention, by employing the bridge arm parallel protection switches, the bridge arm short circuit fault time duration of the modular multilevel converter is shortened; the direct-current bias voltage borne by a transformer and the overvoltage borne by converter bridge arms are reduced; the equipment requirement and cost are lowered; and the economical efficiency and security are improved.
Owner:STATE GRID CORP OF CHINA +2
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