Method of control and repair of wire insulation
SUBSTANCE: method of control and repair of winding wire insulation involves detecting a defect in the insulation of a moving wire by control devices and measuring its extent. Further, when passing a defective area under the enamel application unit, an electrostatically charged enamelling lacquer is applied to the detected defect. For high-strength heat-resistant enamelled winding wires PETV, the enamel insulation of which is made of PE-939 lacquer, a composition for electrostatic coating of film binder on the defective area, for which the liquid PE-939 lacquer of B grade is added with dioxane and the surface tension coefficient is controlled. Then, when the specified coefficient reaches the values (4÷5)⋅106 N/cm, the dilution of the lacquer with dioxane is terminated and 1% ammonia is added to the resulting composition, while measuring the specific resistance of the mixture obtained. Addition of ammonia is stopped when the composition reaches the value of the volume resistivity lying in the range of (10-5÷10-6) Om-1 m-1. Thereafter, said mixture is electrostatically charged by passing it through a nozzle to which a negative high voltage potential pulse is applied in the range of (-2÷-4) kV, the duration of which is equal to the time of passing the defective area under the nozzle. After the application of the liquid enamel film to the defective area excess enamel is removed, then the defective area with the liquid enamel applied to it is subjected to baking and drying.
EFFECT: increasing the accuracy of detection of defective areas in the insulation of the wire and their extent with further repairs, improving the efficiency of repair.
FIELD: electrical engineering; design features of induction apparatuses for cable connection and repairs.
SUBSTANCE: proposed induction apparatus has laminated core with odd number of legs, each carrying inductor coils, as well as two ferromagnetic steel half-molds with inserts mounted on magnetic core loose ends; plane of half-mold split joint is aligned with direction of magnetic flux in mentioned legs. Electromagnetic shunts assembled of set of electric steel plates are installed on external surfaces of half-molds; only first copper or brass insert is electrically connected in half-molds to their edges, this electrical connection being made both in left- and right-hand parts of half-molds and its total length amounting to width of extreme leg and half the distance between extreme and central legs. Next inserts of half-molds are made of metal immune to frictional sparking.
EFFECT: enlarged functional capabilities, reduced consumption of high-cost copper due to highly uniform temperature field built up by apparatus.
5 cl, 20 dwg
SUBSTANCE: method consists in measurement of active and reactive components of zero sequence current and phase voltage of damaged lines in emergency mode and subsequent calculation of inductive resistance to each place of earth fault proportional to the distance to places of damages.
EFFECT: improvement of accuracy of finding of distance to places of double earth faults on power lines.
SUBSTANCE: it comprises a helicopter type aircraft, a control system, control units of overhead power transmission lines connected to the accumulator located in the housing, and the drive system connected to an engine and implemented with a possibility of fixing of position of the diagnostics device with reference to the lightning-protective cable or power wire and ensuring its movement along and near overhead power transmission lines. The helicopter type aircraft is connected to the battery, it includes a control system and is attached to the housing from outer side. The housing is fitted with guides, implemented with a possibility of setting of trajectory of movement of a lightning-protective cable or a power wire in the device up to the position allowing to fix the device on a lightning-protective cable or a power wire.
EFFECT: expansion of range of tools, simplification of process of installation of the device for diagnostics of overhead power transmission lines on a lightning-protective cable or a power wire.
6 cl, 3 dwg
SUBSTANCE: proposed method consists in measurement of active and reactive components of phase current and voltage under emergency. Then, inductive reactance is calculated to every earth point proportional to distance to pints of faults.
EFFECT: higher accuracy of determination.
SUBSTANCE: monitor comprises two sensors sensing the strength of an external magnetic field, which are placed at current feeding and draining wires coupling the load to a single-phase bridge rectifier. At that outputs of sensing elements of the field strength sensors are connected to the first and second input of the comparator respectively through the relevant analogue amplifiers and narrow-band filters, while the output of the comparator is coupled to an indicator.
EFFECT: potential identification of leakage current in the load of a single-phase bridge rectifier by a non-contact way in real time without the disconnection of the rectifier from the functioning process.
FIELD: aircraft engineering.
SUBSTANCE: in compliance with this process, power line buzzing is performed. Note here that drone control board is used. ACS and electric field intensity meter are installed as this drone. Drone coordinates are defined with the help of satellite navigation system. Vertical, horizontal-lengthwise and horizontal-crosswise components of the 50Hz-line electric field are measured. Drone flight along power line is stabilized in altitude and heading.
EFFECT: control with no interference of operator.
SUBSTANCE: electromagnetic waves occurring in the place of fault and propagating towards the line ends are identified. At the moments of arrival of the wave fronts to the line ends the difference of times of arrival of fronts of electromagnetic waves to the line ends are measured and registered. Before the fault localisation the faults are simulated in view of features of the high voltage line and the subsequent registration of time of arrival of electromagnetic waves to the line ends. By results of simulation the adjusting factors are determined. The fault is localised by summation of half of the line length, half of product of the difference of time of arrival of waves with the speed of propagation of electromagnetic waves, and also the adjusting factor.
EFFECT: higher accuracy.
1 tbl, 1 dwg
FIELD: machine building.
SUBSTANCE: according to the method the active and reactive resistances are measured to the short circuit point as per emergency values of current, voltage, and angular displacement between them at the moment of voltage occurrence. With setpoints the distance between place of protection installation and short circuit point is compared, it is determined based on weighed averaging of distance evaluations received considering changes of active and reactive resistances. Upon smooth change of the operation mode parameters of the line the protection is disabled until protection enabling upon reset of short-term operation mode of the power transmission line. Change of the mode parameters is registered as per changes of sign of the distance between the protection installation point and short circuit point. Additionally based on the emergency values of current, voltage and angle of displacement between them at least one procedure of damage point determination of the power transmission lien is made with reception of the distance evaluations to the shirt circuit point. The weighed average evaluation or evaluation is provided for the distance between the protection installation point and shirt circuit point.
EFFECT: improved operation stability of the remote protection.
FIELD: measurement equipment.
SUBSTANCE: invention relates to measurement equipment, in particular, to facilities for control of overhead power transmission lines. The device comprises a body, through which the power transmission line passes, and a side part, which closes both ends of the body. At the same time the body comprises a GPS module interacting with a satellite with the help of antennas distanced in space and formed on the side part, and also a module of sensors for condition of the overhead line or condition of the environment. Also the device comprises the first and second wireless modules and an antenna switchboard, made as capable to implement communication with another control device, a control unit, providing for switching of the antenna switchboard for connection to antennas of the first and second wireless modules. The control unit is made as capable of transmission with the help of directional antennas of control information, including information on condition of the line and information of the GPS system. The device also comprises an infrared or a digital chamber, a mobile communication module, a memory, a power supply unit, made in the form of an accumulator or a supercapacitor. Radio modules may be modules based on ZigBee, WiFi, Bluetooth technologies.
EFFECT: increased reliability of information transmission, reduced power supply losses.
11 cl, 5 dwg
SUBSTANCE: antenna assembly mounted at the device of control and diagnostics in power supply line comprises a load-bearing part made of insulating dielectric material with the preset thickness and curved shape of outer and inner surface, antenna radiator shaped as curved surface along the outer surface of the load-bearing part, earthing element shaped as curved surface along the outer surface of the load-bearing part and exciting part passing through the load-bearing part for electrical connection of the antenna radiator and earthing element. The antenna assembly is mounted at one side of the device to control and diagnose the power supply line in direction of the power supply line when the device of control and diagnostics is mounted in the power supply line.
EFFECT: reduced interference, high amplification factor, efficiency factor, potential miniaturisation, minimisation of temperature impact and increased service life.
15 cl, 16 dwg
SUBSTANCE: models of two parts of a feeder are compiled, the first - from the observation place to the place of supposed fault and the second - from the place of supposed fault to the feeder end, the first part of the feeder is simulated using straight line and a zero sequence, and the second one - using only a zero sequence, non-zero components of the registered currents and voltage of the damaged phase in the place of supposed fault are converted into the direct sequence models into a non-zero component of voltage of the damaged phase, the zero components of the registered currents and voltages are converted into zero sequence models of the first part of the feeder into zero sequence voltage in the place of supposed fault and into zero sequence current to this place, two named voltages are summarised, forming a voltage of the damaged phase in the place of supposed fault, the zero sequence voltage is fed in the place of supposed fault to the input of the zero sequence model of the second part of the feeder and the current on its input is fixed which is subtracted from the zero sequence current to this place, forming current of supposed fault, voltage and current are multiplied in a place of supposed fault, forming a signal of instant power of the supposed place of short circuit, the sign of this signal is determined and a real short circuit is fixed in the place where the named signal during its change remains non-negative.
EFFECT: improving accuracy.
FIELD: instrumentation engineering; three-phase single-ended insulated- or compensated-neutral supply mains.
SUBSTANCE: proposed method involves detection of first failed phase on occurrence of single-phase ground fault, disconnection of power-transmission line from power supply, shorting-out of first failed phase and conductor of second serviceable phase at certain distance in end of power transmission line, grounding of neutral point of power supply or lead of one of its serviceable phases, connection of power transmission line to power supply, and measurement of emergency parameters. Chosen out of emergency parameters are current through first failed phase, current through second serviceable phase, and phase angles of these currents relative to voltage between mentioned first and second phases. Distance to point of single-phase ground fault is found from expression interrelating mentioned parameters.
EFFECT: enhanced measurement accuracy, facilitated location of single-phase ground fault.
1 cl, 1 dwg
FIELD: instrumentation engineering.
SUBSTANCE: proposed device designed for detecting faulty outgoing line of 6- 10 kV insulated-neutral network on occurrence of single-phase ground fault in this network makes it possible to tune away from aperiodic component of singe-phase ground fault process, to eliminate malfunction during damped oscillations of zero-sequence current and voltage signals, and to save information about faulty line number. Device also provides for resetting zero-sequence current and voltage phase comparison element in preset time upon elimination of single-phase ground fault.
EFFECT: enlarged functional capabilities of device.
1 cl, 1 dwg
FIELD: service of distribution of 6-10 kV electric networks.
SUBSTANCE: indicator can be used for finding damaged parts in distribution network at short circuit breakdown. Indicator is installed in distribution and transformer stations and has plate made of material having paramagnetic, diamagnetic or ferromagnetic properties, vertical axis of rotation and horizontal arm. Top and lower ends of plate are bent to one side at angle of 90 deg and have several pairs of holes disposed symmetrically to adjust torque. Plate is mounted with selected pair of holes onto vertical axis of rotation which has lower end fixed to horizontal arm. Arm is attached to vertical member of bus.
EFFECT: simplification of design; reliability of operation.
FIELD: maintenance of aerial power lines with an insulated neutral conductor by contactless method, applicable for mobile location of a single-phase ground fault in a branched aerial power line with an insulated neutral conductor.
SUBSTANCE: the method provides for fixation of an emergency signal, then the electric and magnetic field strengths are measured as an emergency signal in succession in the point of branching and under each branch of the aerial power line, converted to harmonic components of the voltage and current signals proportional to them, with the aid of the Fourier transform for each harmonic the amplitude and the phase angles of the harmonic components of the voltage and current signals are determined, from the sequence of the values of the amplitudes of harmonic components of the voltage and current signals the i-th harmonic component with the maximum amplitudes of harmonic components of the voltage and current signals is separated, comparing them with the proportional maximum allowable amplitudes measured in the normal operating conditions of the power line, and according to the excess of the values of the amplitudes of the components of the voltage and current components of the separated i-th harmonic, the branch with a faulty condition, the direction to the point of the ground fault in it are determined according to the sign of the shift between the harmonic components of the voltage and current signals of the separated i-th harmonic, for the positive sign of the phase shift angle between the harmonic components of the voltage and current signals the direction of search "to the right" corresponds, and for the negative sign of the phase shift angle between the harmonic components of the voltage and current signals the direction of search "to the left" corresponds, the point of ground fault in this branch is determined according to the change of the sign of the phase angle shift between the harmonic components of the voltage and current signals of the separated i-th harmonic, measuring the strengths of the electric and magnetic fields, moving under the aerial power line along the faulty branch.
EFFECT: provided determination of the point of the single-phase ground fault within a short period of time with a high precision and convenience.
1 dwg, 6 tbl
FIELD: electrical measurement technology.
SUBSTANCE: first phase with damage insulation is found and power line is switched off of three-phase power line. Second and third phases with non-damaged insulation are closed to ground by means of jumpers at beginning and end of power line at known distance from start point of power line. Single-phase ac source is removed from beginning of power line between first phase with damaged insulation and ground. Voltage between first phase with damaged insulation and ground at beginning of power line is measured, then current is measured in first phase as well as phase angle between the voltages and current. After it distance to single-phase short-circuit is determined.
EFFECT: increased precision of measurement.
FIELD: electrical power engineering.
SUBSTANCE: method concludes in registering voltage of damaged phase at buses of power supply in digital form and subsequent analyzing that voltage. Voltage to be measured is standardized from the moment of beginning of short-circuit in relation to breakdown voltage and sums of standard deviations
of measured standardized voltage um,i relatively to multiple calculated voltage curves uc,i,k derived preliminary in digital form for damaged chain of lines of the circuits. Numerical modeling of process of single-phase short-circuit is carried out for different distances to supply point. Distance to point of short-circuit is found from minimal standard deviation corresponding to specific calculated curve without avoiding switching power supply of damaged line off.
EFFECT: improved precision.