169 results about "Metal oxide surge arrester" patented technology

The invention discloses an electrified tester for a zinc oxide arrester, and relates to an instrument for detecting alternating-current parameters of a metallic oxide arrester in an electrical power system in the process of charged running. The electrified tester comprises a master machine and a slave machine; a current sensor lead wire, a current sensor unit, a program control amplification unit, a current signal processing control unit and a wireless signal receiving module are connected sequentially and are connected with an upper computer; the upper computer is respectively connected with the current signal processing control unit, a liquid crystal display, a keyboard and a mouse to form the master machine; a voltage sensor lead wire, a voltage sensor unit, a voltage signal processing control unit and a wireless signal emission module are connected sequentially to form the slave machine; and the master machine and the slave machine control signals and data through wireless communication transmission. The electrified tester is suitable for detecting total leakage current, resistive current fundamental waves and triple frequency harmonic at regular intervals on the running metallic oxide arrester and checking the running performance of the metallic oxide arrester.

The invention provides a method for extracting the resistive current of a metal oxide arrester (MOA). The technical scheme comprises the following steps of: acquiring a voltage signal applied to the arrester and leakage current flowing through the MOA and performing fast Fourier transform on the voltage signal to acquire the amplitude and phase of each subharmonic; acquiring a capacitive current signal of which the waveform is the same as that of capacitive current of the arrester and the amplitude is in proportion to that of the capacitive current of the arrester according to a phase relationship between a voltage signal and a current signal on a capacitor and the acquired amplitude and phase of each subharmonic of voltage; and acquiring the resistive current of the arrester according to the principle that the resistive current is orthogonal to the capacitive current of the arrester. The method has a rigorous principle and is convenient to implement; a digital signal has high anti-jamming capability; phase shift is processed by the fast Fourier transform, so even if each subharmonic exists theoretically, errors cannot be generated; and the measurement accuracy of the resistive current can be effectively improved in practical application.

The invention belongs to the technical field of electric power on-line monitoring, relating to an on-line monitoring device of a metallic oxide arrester. The on-line monitoring device comprises a protecting circuit, a movement time detecting unit, a leakage current sampling circuit and a collecting board, wherein, the upper end of a varistor in the protecting circuit is connected with a metal oxide arrester (MOA), and the lower end thereof is grounded; the movement time detecting unit is connected with a leakage current sampling unit in series and then is connected with an output end of the choke coil in the protecting circuit; an output end of the movement time detecting unit is connected with one path of input end of the collecting board; an output end of the leakage current sampling unit is connected with the other path of input end of the collecting board; the collecting board is used for collecting signals and realizing on-site display and data remote transmission; a computer monitoring center collects information from the collecting board so as to carry out analysis treatment and fault alarming.

The invention discloses a residual voltage test circuit of a controllable metal oxide arrester and a method thereof. The test circuit comprises an impulse current generation device, an impulse modulation capacitor, a voltage divider, a Rogowski coil and a wave form recorder; wherein the impulse current generation device generates operation impulse current and/or lightning impulse current, and is provided with a high voltage output end and a low voltage output end; the impulse modulation capacitor is connected in parallel with a controllable arrester sample between the high voltage output end and the low voltage output end; one end of the voltage divider is connected with the high voltage output end of the impulse current generation device, while the other end is earthed; the Rogowski coil is directly sleeved on a conductor on a branch circuit of the controllable arrester sample; the wave form recorder is connected with the voltage divider and the output end of the Rogowski coil respectively, and is used for recording voltage and current wave form of the controllable arrester sample. The residual voltage test circuit for the controllable arrester and the method thereof prolong wave head time of the residual voltage on the controllable arrester sample by using the impulse modulation capacitor without changing parameters of the test circuit or the wave form of the lightning impulse current, so that tests have better system equivalence.

Provided is a metal oxide arrester multiple-lightning-current withstand test method which comprises the steps of selecting a valve plate and recording a test environment, recording the performances of the valve plate before test, determining parameters for multiple lightning current applying, recording the test process in which multiple lightning current impulse is applied to the valve plate, measuring the performances of the valve plate after test and evaluating the capability of the valve plate to withstand multiple lightning current. According to the metal oxide arrester multiple-lightning-current withstand test method provided by the invention, the situation of an arrester under the action of actual lightning current including first lightning current, subsequent lightning current and immediate long-time lightning current can be simulated, and the test method is feasible.

The invention discloses a controllable metal oxide arrester action characteristic testing device and a method therefor. The method comprises: the sphere gap spacing in an impulse voltage generator isregulated, impulse voltage with the peak value higher than the action threshold value of a controllable metal oxide arrester sample is applied on the controllable metal oxide arrester sample for a plurality of times, and the voltage value of the controllable metal oxide arrester sample at the action moment can be obtained by recording the voltage value of the sample at the action moment. The action characteristic testing method of the controllable arrester has good system equivalence under the conditions of power frequency, operation and lightning impulse voltage, so as to comprehensively testthe action characteristics of the controllable arrester in an actual system under various voltages.

The invention discloses a distributed wireless synchronous zinc oxide lightning arrester online monitoring apparatus. The apparatus comprises a cloud server, station wireless servers, lightning arrester leakage current acquisition units, reference voltage acquisition units, a network terminal and an onsite terminal. The cloud server is a bought or rented cloud-end server and runs lightning arrester monitoring management server software; each station wireless server comprises a wireless local area network access module, a radio frequency clock time service main station, a wireless mobile network communication module, a master control module and a battery; and the lightning arrester leakage current acquisition units and the reference voltage acquisition units each comprises a voltage transformer, a voltage signal conditioning circuit, an AD, a CPU, a GPS/BD clock time service module, a radio frequency clock synchronous module, a wireless network card, an antenna, a display screen and a battery. The apparatus provided by the invention is applied to online monitoring of the states of metal oxide lightning arresters, the work states of all the lightning arresters are uploaded to the cloud server through networks, and equipment states are checked through random networking of onsite terminals.

The invention relates to the field of manufacturing high voltage metal oxide surge arresters and discloses a formula of a non-linear resistor for a high voltage surge arrester and a manufacturing method thereof, which are applicable to the metal oxide surge arresters for protecting high voltage power devices, in particular to the metal oxide surge arresters of ultra-high voltage AC power transmission and transformation systems of 750kV and 1000kV. The formula comprises additives consisting of the following components by weight percent: 3.1-4.8% of bismuth oxide, 2.5-4.6% of antimony oxide, 1.2-2.6% of cobalt oxide, 0.7-1.5% of silicon oxide, 0.5-0.9% of manganese oxide, 0.7-1.3% of chromium oxide, 0.3-0.9% of nickel oxide, 0.04-0.13% of boron glass powder and 0.01-0.06% of aluminum oxide. The balance is a main component-zinc oxide.

The invention discloses an explosion-proof automatic-separation type lightning arrester comprising an insulating cylinder and a silastic jacket, wherein the insulating cylinder is internally provided with a plurality of layers of fixed zinc oxide valve sheets; the lower end of the insulating cylinder is provided with grounding wires conductively connected with the zinc oxide valve sheets; a radiating ventilation groove is arranged around the zinc oxide valve sheets; the lower end of the insulating cylinder is fixed with an explosion-proof separation cover in a sealing way; the inner side of the explosion-proof separation cover in the insulating cylinder is provided with a chemical material part and a hot melt separation part; the end surface of the explosion-proof separation cover is provided with a safety groove communicated with the radiating ventilation groove; and internal flashover generated due to the strong thunder or high-pressure gases generated by violent reaction when the chemical material is heated causes the safety groove to break, thus leading the explosion-proof separation cover to being separated from the insulating cylinder. The explosion-proof automatic-separation type lightning arrester has good separation reliability, the reliable separation not only can be realized under the conditions of aging of the metal oxide arrester and slowly increasing of leakage current, but also can be realized under the condition of internal flashover damage when the lightning arrester is impacted by the strong thunder, and comminuted explosion and permanent ground fault do not occur, thus ensuring the normal operation of electric power systems.

The controllable arrester in metal oxide includes control part and fixed part connected in series. In normal operation of system, the control part and the fixed part together bear system voltage. When amplitude value of system over voltage exceeds prearranged threshold value, the fixed part bears system over voltage. Combining power electronic device in large power with arrester in metal oxide (MO), the invention puts forward concept and designing idea of controllable arrester for aiming at issue of over voltage protection for transmission system in super voltage, extra high voltage. Based on condition of maintaining invariable performance parameters of MO resistance piece, the invention reduces residual voltage of arrester effectively by using characteristics: quick response speed of power electronic device, steady operation, and flexible adjustment so as to raise protection level for arrester.

The preparation method for leadless sealing glass in metal-oxide arreaster comprises: mixing evenly all of the 20~30% V2O5, 18~24% B2O3, 45~55% ZnO, 0~3% P2O5, 0~10% Bi2O3, 0~5% MO3 and 0~5%Á€BaO; adding the materials into the corundum crucible or bisque crucible of 900Deg for fusing at 1000~1100Deg and holding for 20~40min; then, putting the cooled glass into a ball grinder; finally, screening the grinded glass with screen of 300 items. This invention has no PbO or alkali metal oxide, needs only low temperature for fusing and sealing, and fit to match seal.

The invention relates to an overvoltage computing method of a modular multi-level converter. An electromagnetic field theory is used in the method to compute converter stray parameters and build an overvoltage computing model, a circuit theory is used to compute overvoltage of converter electrical grids to the ground and between the electrical grids, the overvoltage is classified and analyzed based on metallic oxide arrester protection properties, and the method comprises the steps of extracting modular multi-level converter stray parameters, building a modular multi-level converter overvoltage model, and computing converter biggest overvoltage according to the arrester protection properties. By means of the overvoltage computing model, computing errors generated by assumed extraction of the stray parameters using equivalent capacitors or plate capacitors are avoided, overvoltage computing accuracy degree is improved, a protection level for direct protection of the modular multi-level converter arrester is confirmed, classification of modular multi-level converter overvoltage computing is simplified, overvoltage analysis difficulty and workload are lowered, device safety is ensured, and overvoltage analysis efficiency is improved.

The invention relates to a comprehensive live test method of insulation defects of a metal oxide arrester for electric power. The method includes the following steps that firstly, a three-phase leakage current value is detected through a tong-type ammeter; secondly, the metal oxide arrester is tested through an arrestor resistive current tester; thirdly, the metal oxide arrester is detected through an infrared thermal imager; fourthly, high-frequency partial discharge detection data of the metal oxide arrester are analyzed, and whether discharging exists in the metal oxide arrester or not is determined; fifthly, the outer insulating surface of the metal oxide arrester is subjected to corona discharge detection through an ultraviolet imager. By adopting the method, counter defects and insulating defects like inner damping or valve slice aging of the metal oxide arrester for electric power can be quickly detected and positioned, and working efficiency is improved; the method has the advantages that power failure does not exist, the structure is simple, efficiency is high, and a visual effect can be achieved.

The invention discloses a fault prediction method of power transformation primary equipment. The method comprises the fault predication of a transformer, an isolating switch and a circuit breaker. The fault predication of the aspects of the transformer, the isolating switch, the circuit breaker and a metal oxide lightning arrester is mainly carried out, through the combination of various advanced technology of electronics, computer, photoelectricity, signal processing and sensing, and the fault predication and rapidness and accuracy of detection are realized. According to the method, the potential fault of power equipment can be early found, an early warning or prescribed operation is provided for the operation of the power equipment, and thus the stable and safe operation of a power grid is ensured.

The invention discloses a method and device for detecting a metal oxide arrester resistive current. The method includes the following steps that 1, a parameter current is collected; 2, on the basis that the dielectric loss factor, tested in a black-out test and being the same with that of a metal oxide arrester, of a current transformer is tan delta, the phase included angle between a leakage current signal I1 and an end current of the current transformer is delta; the phase difference between the fundamental wave of the leakage current signal I1 and the fundamental wave of a full current signal I0 is alpha; through calculation, the resistive current IR satisfies the following formula that IR is equal to sin (delta+alpha)* I0. The device comprises a signal connecting cable, a portable measuring instrument and more than two zero flux core-through-type micro-current sensors. The method and device for detecting the metal oxide arrester resistive current have the advantages that under the condition that a terminal voltage is not measured, accurate measurement of the metal oxide arrester resistive current is achieved, a secondary terminal of a voltage transformer does not need to be operated, the detection safety and the detection stability are improved, operation is easy, measurement is accurate, and field operation can be performed easily.

The invention discloses a metal oxide arrester resistance current extracting method and a device. The method comprises steps: initial leakage current at a zero crossing point of the metal oxide arrester is firstly acquired; frequency of the leakage current at the zero crossing point is detected and determined, the frequency of the initial leakage current is delayed by a 1/4 cycle via a delaying circuit, and new leakage current is obtained; summation is carried out on the obtained new leakage current and the initial leakage current via a summer, and combined leakage current is obtained; through detecting a time corresponding to a combined wave peak value, capacitive leakage current is generated; and the capacitive current is finally subtracted from the initial leakage current via a subtracter, and the resistance current of the metal oxide arrester is obtained. The device comprises a low-pass filter, an analog to digital conversion module, a zero-crossing detector, a frequency detector, a delayer, the summer, a peak value time detector, an automatic signal generation unit and the subtracter. In the condition of not measuring the voltage signals, capacitive current is removed in the leakage current, resistance current is obtained, the purpose of aging monitoring on the MOA can be achieved, and risks of measuring high voltage can be avoided.

The present invention discloses an electrical equivalent model of a metal oxide arrester varistor under action of VFTO, comprising a linear inductor (L1), a nonlinear resistor (R1), a linear resistor (R0), and a linear capacitor (C0). The linear inductor (L1) and the nonlinear resistor (R1) form a first serial branch, the linear resistor (R0) and the linear capacitor (C0) form a second serial branch, the first serial branch and the second serial branch form a parallel branch, one end of the parallel branch is a low-voltage end, and the other end of the parallel branch is a high-voltage end. When an external voltage is lower than an impedance breakover voltage U0, a current that flows through the R0C0 branch is greater than a current that flows through the R1L1 branch, an MOV mainly externally presents a capacitive impedance feature. When the external voltage is higher than the impedance breakover voltage U0, the current that flows through the R0C0 branch is greater than the current that flows through the R1L1 branch, the MOV externally presents an inductive impedance feature. The electrical equivalent model provided by the present invention is used for simulation calculation of MOV features under the action of the VFTO.

The invention discloses a metal oxide arrester. The metal oxide arrester comprises a hollow insulating cylinder, an upper metal sealing plate, a lower metal sealing plate, a conducting post and a cluster parachute, wherein the upper metal sealing plate is arranged on the upper end of the hollow insulating cylinder, the lower metal sealing plate is arranged on the lower end of the hollow insulating cylinder, the conducting post is axially arranged in the hollow insulating cylinder, the cluster parachute covers the outer surface of the hollow insulating cylinder, a gap radially exists between the hollow insulating cylinder and the conducting post, the upper end of the conducting post makes contact with the upper metal sealing plate, the lower end of the conducting post makes contact with the lower metal sealing plate, and the conducting post is formed in a way that zinc oxide resistance discs and metal conductors are alternately overlapped. The invention provides the metal oxide arrester with high heat dissipation performance, and the problem of easiness in thermal breakdown and thermal explosion of a metal oxide arrester with an existing structure is solved.

The invention discloses a metallic oxide lightning arrester leakage current live test device and method. The test device comprises a noninductive shielding resistance and a lightning arrester leakage current tester, the noninductive shielding resistance is connected to a grounding wire of the metallic oxide lightning arrester in series, and disturbance of the surrounding electromagnetic environment for a leakage current can be shielded by the noninductive shielding resistance; a voltage transformer is connected with the two ends of the metallic oxide lightning arrester in parallel, the leakage current input end of the lightning arrester leakage current tester is electrically connected with the noninductive shielding resistance, and the input end of a reference voltage is electrically connected with a secondary voltage terminal of the voltage transformer. An analysis is carried out by the lightning arrester leakage current tester according to phase changes of the waveforms of a collected reference voltage signal and a leakage current signal, and the aging degree of the metallic oxide lightning arrester can be determined. According to the metallic oxide lightning arrester leakage current live test device and method, the metallic oxide lightning arrester leakage current can be simply, precisely and effectively tested, and the aging degree of the metallic oxide lightning arrester can be analyzed.

The invention relates to the manufacturing field of non-linear metal oxide lightning arresters and discloses a raw material formulation of high-gradient non-linear resistance card and a manufacturing method thereof suitable for small-sized metal oxide lightning arrester of extra-high voltage power equipment. The raw material formulation of high-gradient non-linear resistance card comprises the following components according to mol percentages: additives comprising 0.5-1.5 mol% of Bi2O3, 0.7-1.2 mol% of Co2O3, 0.4-0.9 mol% of MnCO3, 0.7-1.5 mol% of Sb2O3, 0.2-0.8 mol% of Cr2O3, 0.5-1.1 mol% of SiO2, 0.3-1.2 mol% of Y2O3, and the remained ZnO as the main material. The manufacturing method thereof comprises the following steps: preparing additive; ball milling; sintering; mixing ZnO and additive; mixing dispersant; spraying and granulating; forming; sintering; polishing card; thermally processing; spraying aluminum; forming the organic insulated layer.

The invention provides a high-temperature silicone rubber material resistant to strong ultraviolet radiation. The high-temperature silicone rubber material resistant to strong ultraviolet radiation is prepared from, by mass, 3-6 parts of nano titanium dioxide, 3-6 parts of diphenyl ketone, 75-85 parts of methyl vinyl silicone rubber I, 15-25 parts of methyl vinyl silicone rubber II, 20-30 parts of white carbon black, 95-105 parts of aluminum hydroxide micro-powder, 3-7 parts of zinc oxide, 2-5 parts of iron oxide red, 4-8 parts of hydroxyl silicone oil, 2-5 parts of methyl silicone oil and 2-5 parts of a vulcanizing agent. The high-temperature silicone rubber material can absorb ultraviolet rays, has an extremely strong strong-ultraviolet-irradiation resisting function, is applied to a compound metal oxide lightning arrester sheath used in a high-altitude area and can delay the aging of a metal oxide lightning arrester and ensure the safe operation of a power system.

The invention discloses an online monitoring device and a monitoring method for a metallic oxide arrester. The device comprises a main control chip, a data acquisition module for acquiring leakage current signals and voltage signals, a background algorithm processing module for receiving the data of the data acquisition module, calculating the value of a resistive current and transmitting the value to the main control chip, and a man-machine interaction assembly in interactive connection with the main control chip. The data acquisition module comprises a voltage and current measuring module for measuring the voltage at the two ends of the metal oxide arrester and the leakage current of the metal oxide arrester, a filtering module for receiving the signal of the voltage and current measuring module and performing the filtering treatment, and a conversion module for receiving the signal of the filtering module and performing the AD conversion. Based on the online monitoring device and the monitoring method for the metallic oxide arrester, the influence of harmonic waves in the voltage on the resistive current extraction is fully considered. Meanwhile, the interference caused by the harmonic voltage on the resistive current extraction can be well reduced. Moreover, the efficiency and the accuracy of online monitoring are improved.

The invention provides a method for extracting the resistance current of a metal oxide arrester (MOA). By the adoption of the method, the influence of harmonic voltages on the resistance current can be eliminated more effectively, the error of i1r and i3r is reduced ultimately, hence, the operation condition of the MOA can be reflected more accurately, and safety operation of a power electrical system is guaranteed. The principle that the capacity current and the capacitance are in proportion is used for solving the capacity current, the equivalent resistance R1 is used for eliminating the harmonic influence, hence, the resistance current (ir) can be calculated more accurately, the ir is used for calculating the i1r and the i3r through an FFT algorithm, and finally on-line monitoring of the MOA is achieved.

The invention discloses a field measurement standard device of an insulated online monitoring device. The device comprises a shell, and a relative dielectric loss and zinc oxide arrester resistive current analog signal generator and a standard tester, which are arranged in the shell; a first current output terminal, a second current output terminal and a voltage output terminal connected with the relative dielectric loss and zinc oxide arrester resistive current analog signal generator are arranged on the shell, a first current signal is transmitted by the first current output terminal onto a detected online monitoring device, and the first current signal is further transmitted onto the standard tester through a first high precision punch current transformer arranged in the shell; a switching device is further arranged in the shell. The field measurement standard device disclosed by the invention has the advantages of reasonable design, simple structure, small volume, light weight and simple operation, and the field measurement standard device can be used for verifying the dielectric loss factor and the capacitance of capacitive equipment on site and verifying the online or charged test device of resistive current or capacitive current of a metal oxide arrester.

The invention discloses a method for obtaining potential distribution of an 800kV direct current bus metallic oxide arrester. The method comprises the steps of (1), simulating the potential distribution when the metallic oxide arrester operates normally, wherein the step (1) comprises the sub-steps of (1-1), establishing a three-dimensional mathematical model for the potential distribution of the metallic oxide arrester, (1-2), assigning resistivity according to a material attribute of each component of the metallic oxide arrester, and (1-3), applying a forced potential boundary condition; and (2), carrying out resolution calculation on the three-dimensional mathematical model according to the assigned resistivity and the forced potential boundary condition, thereby obtaining the potential distribution when short circuits occur in resistors at different positions or the resistors are damped. According to the method, the complete three-dimensional model of the 800kV direct current bus zinc oxide arrester is established according to the actual size parameter of each component of the arrester; the periphery space of the arrester is simulated through a limited air domain; the potential of a suspension conductor is processed through utilization of degree of freedom coupling in ANSYS; a calculation scale is simplified; and moreover, the potential distribution of the arrester is calculated accurately.