Device for detecting partial discharges
SUBSTANCE: device for detecting partial discharges comprises high-voltage direct-current power supply source with high-voltage capacitor connected to it through one position of switch key; through the second position of switch key the tested facility is connected with a sensor connected to the facility. Oscilloscope is coupled to the sensor through a shielded wire. Direct-current power supply source, capacitor and sensor are interconnected at common point and grounded. The technical effect is as follows: device for detecting partial discharges allows diagnosing direct-current machines.
EFFECT: potential detection of partial discharge signals in insulation of direct-current motors.
The invention relates to the field of measurement of electrical quantities and can be used to detect signals of partial discharges in electrical insulation of DC motors in the diagnosis of defects of isolation.
A device for measuring partial discharges [RU 2402092 C1, IPC NN 9/50 (2006.01), publ. 20.10.2010], contains located inside the electrostatic screen and having a common grounding a partial discharge sensor, made in the form of inductors, analog-to-digital and optical converters and a common power supply converters. The input of analog-to-digital Converter connected with potential output inductors and the output of which is connected to the input of the optical Converter, the output of which is connected an optical cable connected to an external measuring device. The device comprises an amplifier with a negative gain and is supplied with a signal and Pogranichnaya windings disposed on an electrostatic screen. The signal winding is connected to the input of the amplifier, the output of which is connected Pogranichnaya winding. The elements listed above have a common ground potential.
A device for the continuous monitoring of partial discharges in the insulation of high-voltage three-phase conditions in�the rd operation, comprising at least one active portion in the form of electrically conductive interconnected elements under high voltage and is surrounded by layers of insulation [RU 2393494 C1, IPC G01R 31/02 (2006.01), publ. 27.06.2010]. In addition, this device contains circuitry processing, registration of partial discharge signal and at least one sensor-signal receiver of partial discharges, which is used as the active part of a three-phase high-voltage apparatus. Measuring PD signals produced simultaneously on all three phases of HV apparatus at a common point of the active part of the device with use of low-voltage measuring voltage transformers, connected according to the scheme broken Delta.
A device for controlling characteristics of partial discharges [RU 2019850 C1, MPK G01R 31/12, publ. 15.09.1994], selected as a prototype containing the test transformer, high voltage capacitor, series-connected high-pass filter, measurement cable and instrument recording. One of the capacitor plates is live lived of the test object, which is parallel to the conductive plate, the second plate of the capacitor connected to the input of the high pass filter, made in the form of a segment �whoprovides line with distributed parameters. The capacitance CChigh-voltage capacitor and the impedance of the RHK measuring cable made coaxial, satisfy
where Tand- pulse duration partial discharge.
The evaluation unit includes series-connected integrating broadband amplifier, comparator, pulse counter and indicator.
The total lack of analogues is that these devices diagnosis of partial discharges are working on AC current. For DC machines, such devices are not acceptable.
The object of the invention is to provide a device for detecting partial discharges, allowing to diagnose DC machine.
The task is solved due to the fact that the device for detecting partial discharges as well as in the prototype contains a high voltage capacitor and a logger.
According to the invention parallel to high-voltage power source of direct current high voltage capacitor connected across one of the provisions of the switching key, via another position of which is connected to the capacitor test subject that is connected to the sensor, the recording device used oscilloscope that using shielded wire�d is associated with the sensor, and the source of DC power, a capacitor and the sensor are connected in common and grounded.
Thus, through the use of a power capacitor as a source of pulsed DC voltage, the proposed device allows to detect partial discharges in windings of DC motors that will identify insulation defects at the initial stage of their occurrence.
Fig.1 schematically shows the inventive device.
Device for detecting partial discharge contains a high voltage power supply constant current 1, in parallel to which is connected a high-voltage capacitor 2 via one of the provisions of patch 3 key. Through another switching position of the key 3 to the capacitor 2 connected to the test object 4 (IO), which is connected to the sensor 5 (E), through which the shielded wire is connected with the oscilloscope 6 (Oh). The DC power supply 1, the condenser 2 and sensor 5 (D) are connected in common and grounded.
As the sensor 5 (E) used in a low-inductance resistor.
The proposed device operates as follows. For charging the high-voltage capacitor 2 is used, the power source 1. Charged capacitor 2 switch switching key 3 from the power source 1 to the subject object 4 (IO), e.g.� to the winding section of a DC motor. Upon discharge, the capacitor 2 outputs a pulse DC voltage, which passes through the test object 4 (IO). If the voltage is sufficient, appear partial discharges, which fix the sensor 5 (D) and record the oscilloscope 6 (O), which allows to represent the data in graphs or tables for further processing. Grounding serves as protection from electric shock.
Device for detecting partial discharges containing high-voltage capacitor and the evaluation unit, characterized in that parallel to high-voltage power source of direct current high voltage capacitor connected across one of the provisions of the switching key, via another position of which is connected to the capacitor test subject that is connected to the sensor, the recording device used oscilloscope, through which the shielded wire is connected with the sensor, and the source of DC power, a capacitor and the sensor are connected in common and grounded.
SUBSTANCE: electric arc detector for detection of undesired electric arcs contains an antenna for receipt of the electromagnetic signal representing the electric arc and a discriminator for analysis of the signal from the antenna. The discriminator contains a spectrum analyser designed so that to enable detecting whether the signal represents a normal electric arc or an undesired electric arc. The discriminator is designed so that to enable detecting whether the signal represents a normal electric arc or an undesired electric arc by way of comparing the levels of signal at the signal spectrum frequencies corresponding to at least one partial reference spectrum and defining of an electric arc a normal one if the deviation from the reference spectrum is less than the threshold deviation. Additionally presented is a corresponding method.
EFFECT: establishment of difference between normal and undesired electric arcs.
13 cl, 3 dwg
SUBSTANCE: measurement device of partial discharges includes sensor of partial discharges, which is made in the form of inductance coil, analogue-digital and optic converters, which are all located inside electrostatic screen and having common grounding, and common power supply source of converters; at that, input of analogue-digital converter is connected to potential output of inductance coil, and its output is connected to input of optic converter to the output of which there attached is optic cable connected to external measurement device. Device is equipped with signal and magnetising windings located on electrostatic screen and having common grounding with the above elements, and with amplifier with negative amplification factor; at that, signal winding is connected to amplifier input, and magnetising winding is connected to amplifier output.
EFFECT: increasing interference immunity of measurement device of partial discharges.
3 cl, 1 dwg
FIELD: electrical engineering.
SUBSTANCE: invention is related to devices of high-voltage equipment insulation condition diagnostics in process of operation (insulation condition monitoring). Tire relay contacts are serially connected in the device to element of indication and switch, and winding of time relay is connected to control circuits of high-voltage breakers of distribution device, in which threshold level of partial discharges is monitored. Thereby, false actuations of device are eliminated during operation in insulation monitoring mode by breaking of measuring circuit for the time of switching of high-voltage breakers of distribution device.
EFFECT: elimination of false actuations of device for control of threshold level of partial discharges during operation in mode of insulation condition monitoring.
FIELD: physics, communication.
SUBSTANCE: invention concerns device of contact burn detection in switch contacts of electric commutation device. Contact burn is detected on at least one opening and closing switch contact couple in commutation device. Device includes light guide and detector, where light emitted by at least one light source is fed to light guide and directed over light guide to detector. Light guide is positioned against at least one couple of switch contacts in such pattern that intensity of light fed to light guide and measured by detector decreases at the growth of contact burn particles number, appearing due to contact burn in electric commutation device.
EFFECT: extended equipment inventory for contact-free control of contact burn by optic electronic devices without removal of commutation equipment from its operation place.
11 cl, 6 dwg
FIELD: condition inspection of high-voltage equipment.
SUBSTANCE: partial discharge sensor is made in the form of inductance coil disposed inside electrostatic screen; its potential lead is connected in series with analog-to-digital and optical converters provided with common power unit; optical fiber cable is connected to output of optical converter; partial discharge sensor, both converters, and common power unit are connected to ground through same ground connection; common power unit may be fuel cell battery, storage cell, or converter that functions to convert ac voltage induced in partial discharge sensor into dc voltage.
EFFECT: enhanced noise immunity in partial discharge measurements.
3 cl, 2 dwg
SUBSTANCE: device comprises a facility (70) to determine a value of neutral overall conductivity in the three-line electrical line (30) and facility (70) to detect ground short-circuit in the three-line electrical line (30) against the determined value of neutral overall conductivity and values of one or more preset parameters. The facility (70) comprises a unit to convert the determined neutral overall conductivity from the area of neutral overall conductivity to the area of residual current, a unit to compare in the area of residual current of the converted value of neutral overall conductivity with one or more preset parameters and a unit to detect ground short-circuit based on the comparison.
EFFECT: higher accuracy of detection.
16 cl, 12 dwg
SUBSTANCE: device includes the first and the second CMDS keys, a threshold element, a D-trigger, a diode, a current-setting resistor, the second power source, and an isolating diode.
EFFECT: improving operating reliability of a switching device.
SUBSTANCE: device comprises three inlet circuits for connection to power supply buses and to the product body, and two outlet circuits for connection of a measurement instrument, two groups of electromagnetic relays, a diode and two low-resistance resistors R1 and R2, which are correspondingly connected to each other. At the same time the specified resistors may be made with different par values by resistance and be substantially less than equivalent resistance of load Rl on power supply buses.
EFFECT: increased efficiency due to reduced number of control measurements, elimination of impact from noise and errors of connection of a measurement instrument for reliability of an assembled electrical system of a product, provision of objective nature and validity of control and detection of errors or defects in an assembled electrical system of a product.
2 cl, 1 dwg
SUBSTANCE: invention is related to the area of process systems and may be used to test power supply circuits of an electrical system. The invention concept is as follows: the device contains three input circuits (for connection to supply buses and the system frame) and four output circuits to connect measuring instruments (ohmmeter and megohmmeter), a switch for three positions and four directions, a diode and two low-ohmic resistors R1 and R2 with different rated values of resistance and essentially less equivalent resistance of Rh load to the supply buses (R1≠2)<Rh and electrical couplings between the device components, which ensure safe testing of power supply circuits of the electrical system in process of its assembly.
EFFECT: increase in production rate, exclusion of effect of interference and errors of the measuring instrument connection on reliability of the assembled electrical system, provision of reliable and authentic control and error or defect detection in the assembled electrical system, including fault-to-frame identification for any power supply buses of the assembled electrical system.
2 cl, 1 dwg
SUBSTANCE: invention relates to technological devices and can be used as a part of an automated measuring system together with measuring instruments at control of feed circuits of an electrotechnical system of items in the process. A switching unit includes three input circuits, four output circuits, electromagnetic relays containing contacts and control windings, and control inputs connected to the control windings, and two resistors R1 and R2, and a diode. The relays are combined in two groups. Control circuits of each relay group are connected to each other and to control inputs of the relays. The first input circuit is intended for connection to a “plus” power bus of the item and connected to the first break-make contact (BMC) of the first contact group (FCG). The second input circuit is intended for connection to a “minus” power bus of the item and connected to the second FCG BMC. The third input circuit is intended for connection to the housing of the item and connected to the third FCG BMC and the second contact group (SCG). The first output circuit is intended for connection of the first output of the measuring instrument and is connected to the first normally closed contact (NCC) of SCG. The second output circuit is intended for connection of the second output of the measuring instrument and is connected to the second NCC of SCG. The first NCC of FCG is connected to the first SCG BMC. The second NCC of FCG is connected to the second SCG BMC. The first normally open contacts (NOC) of FCG and SCG are connected to one output of the first resistor R1. The second NOC of FCG and SCG are connected to one output of the second resistor R2. Other outputs of the above resistors are connected to the fourth BMC of FCG and SCG. The third NOC of FCG and the fourth NOC of SCG are connected to the third output circuit intended for connection of the first output of the second measuring instrument. The third NOC of SCG and the fourth NOC of FCG are connected to the fourth output circuit intended for connection of the second output of the second measuring instrument. A diode cathode is connected to the first output circuit, and a diode anode is connected to the second output circuit.
EFFECT: improvement of efficiency.
2 cl, 1 dwg
SUBSTANCE: device comprises a computer as well as a tester of electric circuit parameters and low-voltage switch including two switch matrices for control of electric circuits without active elements or a tester of electric circuit parameters, program-controlled test input source and low-voltage switch including four switch matrices for control of electric circuits with active elements. There are also additional high-voltage tester, high-voltage switch, a harness for connection to contacts of electrical circuits in the tested facility and high-voltage harness for connection to contacts of high-voltage electrical circuits in the tested facility. At that inputs and outputs of the computer through interface main line are coupled to control inputs of the test input source, the tester of electric circuit parameters, the low-voltage switch, the high-voltage tester and high-voltage switch. Coded outputs of the tester of electric circuit parameters and high-voltage tester are connected to the computer through the interface main line. Input and body frame of the tester of electric circuit parameters are connected to common points of the first and second switch matrices of the low-voltage switch. During testing of electric circuits with active elements input and body frame of the test input source are connected to common points of the third and fourth switch matrices of the low-voltage switch. Output and input of the high-voltage tester are connected to common points of the first and second switch matrices of the high-voltage switch. The harness is connected to contacts of the switch matrices of the low-voltage switch. The high-voltage harness is connected to contacts of the switch matrices of the high-voltage switch.
EFFECT: simplification of electric circuits testing.
4 cl, 3 dwg
SUBSTANCE: invention is related to feeder automation unit for alternating-current contact system of railway lines. The invention concept is as follows: the device comprises a signalling device, three switches with auxiliary contacts, voltage transformer, two voltage relays. The primary winding of the transformer is coupled to the contact system by its one end and to the rail by its other end. A coil of the first voltage relay is coupled to the secondary winding of the transformer via normally closed auxiliary contact of the first switch. The signalling device by its one end is coupled to -110V of control voltage and by its other end to the first output of the normally closed contact of the first voltage relay. The second voltage relay has a high actuation setpoint. Its coil is coupled in parallel to the coil of the first voltage relay and by its first output the normally closed contact is coupled to the first output of the normally closed contact of the first voltage relay and by the second output it is coupled to +110V of control voltage via the normally closed auxiliary contact of the third switch. The normally open auxiliary contact of the third switch is coupled by its one end to the second output of the normally closed contact of the first voltage relay and by its other end to +110V of control voltage.
EFFECT: improving reliability for determination of sustained short circuit at double-track lines at emergency shutdown of alternating-current contact system.
SUBSTANCE: invention relates to the method of short-circuit identification (16) in a line (10) of multiphase electrical power supply network with an earthed neutral. Essence: the current and voltage sampling values are accepted and the signal of failure is generated, if the failure assessment made by the electrical protection device (12a) indicates the short-circuit (16), present in the line (10). Instantaneous reference voltage values from accepted before the occurrence of short-circuit (16) instantaneous current and voltage sampling values, and instantaneous comparative voltage values from accepted before the occurrence of short-circuit (16) instantaneous current and voltage sampling values from accepted during the short-circuit (16) instantaneous current and voltage sampling values are calculated. Then the rectified value of the reference voltage from the following one after another instantaneous reference voltage values and rectified comparative voltage value from the following one after another instantaneous comparative voltage values are calculated. The failure signal is generated, if the difference between the rectified comparative voltage value and rectified reference voltage value exceeds the operation threshold value.
EFFECT: improved operation speed.
12 cl, 9 dwg
FIELD: aircraft engineering.
SUBSTANCE: proposed device consists of the main unit and universal connector. The main unit is composed of metal case with digital indicator, LED set and commutator switch, all being arranged at case working surface. Main unit case accommodates the set of transducers. Said set comprises digital multimeter PCBs to check up the resistance of heating elements of helicopter rotor and antitorque rotor blade sections and LED lamps at rotor blade tips (contour lights). Besides, it comprises digital megohmmeter pcb to measure insulance of heaters. Also, it includes PCBs of air compressor with air hose used to create air pressure at testing helicopter rotor blade supercharging pressure. Air compressor controller PCBs for control over air compressor and helicopter rotor blade supercharging pressure. Terminal box with harnesses and power supply are also tested. Universal connector for connection with blade connector comprises plug-type multi-pin connector and air pipe.
EFFECT: higher validity, enhanced control performances, lower material and labour input at servicing.
SUBSTANCE: method consists in measurement of electric parameters of a single-phase high-voltage potential transformer in nominal operation mode, the primary winding of which is connected between the phase wire of the high-voltage line and earth. In stationary mode they measure electric values, for instance, voltage, on terminals of secondary low-voltage windings of at least three single-phase high-voltage potential transformers connected to a wire of a single-phase. Measurements are carried out within single time multiple to the period of voltage oscillations in the grid. Quotients from division of data from the outlet of the secondary winding of each of three transformers into single-type data from the outlet of the secondary winding of the next single-phase high-voltage potential transformer from the remaining ones are compared. Three ratios are produced, in each two of which there are outlet data of one of three single-phase transformers, but in one ratio this output datum is in the numerator, and in the other one - in the denominator. Violations of the technical condition of one of three single-phase transformers are detected, if difference of quotients from divisions at one moment of time in compared transformers exceeds the specified threshold value. That transformer out of three is accepted as the transformer with disturbance of the technical condition, in which the quotient from division, in which its output datum is in the numerator, reduces, while that quotient from division, in which its output datum is in the denominator, rises.
EFFECT: simplified process of diagnostics of technical condition of single-phase high-voltage potential transformers.
FIELD: electric measurements, applicable in check-up of tram and trolleybus electric apparatuses in the process of manufacture and in service.
SUBSTANCE: current in the current source is fed to the current winding of the current relay from the rectifier via a key, choke, shunt. The device uses a pulse-width modulator that controls the keys, slowly varying voltage is applied to the modulating input of the pulse-width modulator that is preliminarily modulated by the rectifier ripple voltage. Besides, use is made of a sample-release circuit of operate (release) currents and voltages. The signals from these circuits are fed to indicators via analog-to-digital converters.
EFFECT: reduced error of determination of operate and release current and voltage relays, enhanced capacity of check-up in the device due to reduced ripples of the source of smoothly varying current.
2 cl, 4 dwg
FIELD: electrical engineering.
SUBSTANCE: device for checking workability of entrance protective automatic switches preventing ignition of electric wires at short-circuits in circuits operating at voltages up to 1000 V has shunting unit. Shunting unit is formed by fuse and switch which are both connected with adjustable sample resistance. Adjustable sample resistance is made in form of adjustable resistance and incandedescent lamp having metal filament. Device is also provided with two output terminals for connecting to output terminals of switch to be checked and to null bus.
EFFECT: widened range of application.
FIELD: electrical engineering.
SUBSTANCE: device has power transformer, conductor, conducting contact surface, area for forming fake short circuit. Conductor is connected to power transformer via measurement unit and contactor. Conducting contact surface links to power transformer via limiting resistance. Area for forming fake short circuit is made in form of uniform layer of powder graphite applied onto conducting contact surface.
EFFECT: steady electric arc at short circuit; reduced number of trials.
FIELD: electric engineering.
SUBSTANCE: voltage divided has high-voltage arm made of R-C-r units connected in series. Each unit has capacitor and low-ohmic damping resistor connected in series with and high-value resistor to shunt the connection. Low-voltage arm of the divided is split to two parts: low-voltage unit and companion unit, both connected together by coaxial cable. Low-voltage unit ha capacitor C2 and low-ohmic resistor r2; capacitor and resistor are both shunted by high-value resistor R2. Companion unit has capacitor C3 connected in parallel high-value resistor R3. Resistor r3 being equal to wave resistance of cable is connected in series with R3. Capacitor C3 is composed of two capacitors connected in parallel to meet the condition of C3=C30+ΔC3. C30 has constant value and ΔC3 has to be adjustable capacitor. Method of compensation of influence of divider capacitance on division factor of divider is based on tuning of division ratio after the final position of diver among rest members of high-voltage testing circuit was found. Calibration voltage U1 of any frequency is applied to divider, output voltage U2 is calculated, division ratios are calculated and values of tuned capacitance are reduced till getting value at which value the division ration would correspond to its nominal meaning.
EFFECT: higher possibility of compensation of capacitance.
4 cl, 3 dwg
FIELD: arrangements for testing electric properties.
SUBSTANCE: method comprises disconnecting the transformer from the power source and rectifier, supplying testing pulse to the phase windings of the transformer from a generator of standard testing voltage pulses of a given amplitude, and measuring current pulse at the shunt connected with the device for measuring current. The shunt is alternately connected between the beginnings of the phase windings of high voltage arranged at the end rods and the core.
EFFECT: reduced labor consumptions and expanded functional capabilities.