Determination method of the circuit insulation resistance and insulation resistance of the joined alternating current circuit with insulated neutral

FIELD: electricity.

SUBSTANCE: measure the average values of the voltage between the positive and negative poles of the three-phase rectifier bridge, assembled on semiconductor diodes according to Larionov's circuit and connected to the phases of AC mains, as well as between the positive and negative poles of the three-phase rectifier bridge and the "ground". At that the voltages grading at the circuit phases is performed, by connecting parallel to the three-phase rectifier bridge poles of two series-connected the first and the second resistors, the common point of which is connected to the "ground". Measure the average value of the current through the wire, connecting the common point of the first and the second resistors with the "ground", measure the average values of the differential currents, flowing through the circuit connections, by means of the sensors of differential currents for measurement of the current average values, after its connecting initially to one of the poles of the third resistor three-phase rectifier bridge, one terminal of which is connected to the common point of the first and second resistors, and then to the other pole of the fourth resistor three-phase rectifier bridge, one terminal of which is connected to the common point of the first and second resistors. The insulation resistance values of the entire circuit as a whole and the insulation resistance values of connections are determined from the corresponding expressions.

EFFECT: extension of functionality by measuring the insulation resistance of connections, reduction of the line-to-earth voltage imbalances value, arising at the circuit insulation resistance and the connections insulation resistance determination.

11 dwg

 



 

Same patents:

FIELD: electricity.

SUBSTANCE: transient resistance of contacts and conductors, total resistance of insulation of the circuit phase - zero, phase - phase, phase - protective conductor without shutdown of power supply, total resistance of insulation of the circuit phase - protective conductor without shutdown of power supply and triggering of the protective shutdown device, total resistance of the line and the circuit, resistance of the grounding devices, the expected short circuit current, differential current of earth leakage, coefficient of absorption and coefficient of polarization. The measured parameters are used for formation of hardware influencing factors in a fuzzy logic system. The distinct hardware influencing factors are normalized for bringing to the same range of their variation. The range of variation of remaining life of electrical wiring in the fuzzy logic system in such a way that at the end of the script conc.m in view of the rounding function round the dependence between the remaining life of electrical wiring, current value of the remaining life of electrical wiring and values of remaining life of the electrical wiring at the worst and best values of hardware influencing factors in view of the maximum service life of electric wiring is established.

EFFECT: improving accuracy of determination of remaining life of electric wiring.

7 tbl, 10 dwg

FIELD: electricity.

SUBSTANCE: in a method of automatic overvoltage protection for high-voltage equipment electric voltage is measured, the range of potential overvoltage is divided into degrees and at each degree respective technical arrangements are carried out to eliminate overvoltage. The symptom of failure of the degree technical arrangements is monitored and when it appears technical arrangements for the next degree are performed. Remaining life is evaluated for the insulation of high-voltage equipment by decreasing its value with the intensity of the consumption rate corresponding to the actual level of overvoltage and the above failure symptom is generated when the remaining life of the insulation is decreased up to a threshold value equal to the production of the time allocated for the performance of technical arrangements for the next degree by the intensity of the consumption rate for the insulation of the high-voltage equipment corresponding to the actual level of overvoltage.

EFFECT: improved operational efficiency of the high-voltage equipment due to more accurate evaluation of the remaining life for the insulation of the high-voltage equipment and increased flexibility in performance of technical arrangements on overvoltage elimination.

3 dwg

FIELD: electricity.

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.

1 dwg

FIELD: electricity.

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

FIELD: electricity.

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.

1 dwg

FIELD: instrumentation.

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

FIELD: electricity.

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

FIELD: instrumentation.

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

FIELD: electricity.

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

FIELD: electricity.

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.

2 dwg

FIELD: electricity.

SUBSTANCE: device contains a source of measuring voltage, milliamperemeter, a galvanic isolation unit, a subtracting unit, a control unit, a control AC voltage source, a first key, a second key, a current-limiting resistor. Two inputs of the galvanic isolation unit are connected to two phases of the monitored network between which there is AC voltage. The output of the galvanic isolation unit is connected to the second input of the control unit the output of which is connected to the input of the controlled AC voltage source the first output of which is connected to the second terminal of the current-limiting resistor the first terminal of which is connected to the second output of the measuring voltage source. The second output of the controlled AC voltage source is connected through the milliamperemeter to earth. The first output of the measuring voltage source through the first key is connected to any phase of the monitored network. The first input of the subtracting unit is connected to the first output of the controlled AC voltage source, and the subtracting unit output through the second key is connected to the first input of the control unit.

EFFECT: reduction of error and time of measurement of isolation resistance.

3 dwg

FIELD: electricity.

SUBSTANCE: invention relates to electrical engineering. The device comprises a resistor connected to the neutral line by its one end, a resistive current sensor, a source of direct-current stabilized voltage, a shunt capacitor C1, RC-filter per 50 Hz, a galvanic decoupler unit, an electronic voltage divider, a differential amplifier, a power supply unit, display and signalling units. At that the second output of the resistor in the neutral line is coupled to the resistive current sensor and the source of direct-current stabilized voltage connected in series. The second output of the resistor in the neutral line is coupled to frame through the shunt capacitor C1, while positive output of the source of direct-current stabilized voltage is connected to the frame through the added resistive current sensor. In parallel to the resistive current sensor there is the RC-filter, which midpoint is coupled to input of the galvanic decoupler unit while output of the latter is coupled to input of the electronic voltage divider; to the divider output the differential amplifier is coupled by its input and to the divider output the display and signalling units are coupled. All units of the device are supplied from the power supply unit.

EFFECT: continuous control of insulation resistance in alternating-current mains with resistive neutral line.

1 dwg

FIELD: electricity.

SUBSTANCE: invention refers to the sphere of electrical engineering. device comprises a source of metered stabilised DC voltage, an RC filter made of serially connected a resistor and a capacitor, one diode, shunting a capacitor C1, a unit of galvanic isolation, an amplifier of signal voltage with a controlled amplification ratio, a power supply unit, an electronic voltage divider, a unit of indication and a unit of alarm. At the same time the source of metered stabilised DC voltage is with a positive pole connected to the body (earth), and with a negative pole is connected to the lower first outlet of the controlled network neutral resistor. The second outlet of the controlled network neutral resistor is connected to the controlled network neutral. In parallel to the source of metered stabilised DC voltage, the capacitor C1 and the diode are connected, and the cathode of the latter is connected to the body (earth). In parallel to the neutral resistor there is an RC filter connected, besides, the filter capacitor is connected in parallel to the inlet of the galvanic isolation unit, which with its outlet is connected to the inlet of the amplifier of signal voltage with the controlled amplification ratio, the outlet of which is connected to the inlet of the electronic voltage divider, and the outlet of the electronic voltage divider is connected directly to the unit of indication and unit of alarm. At the same time all units of the device are energised from the power supply unit.

EFFECT: technical result consists in possibility of continuous control of insulation resistance.

1 dwg

Insulation tester // 2523075

FIELD: instrumentation.

SUBSTANCE: invention relates to electric measurements. Proposed device comprises test voltage source (TVS), reference resistor (RR), charge switch (CS), test object (TO), discharge switch (DS) discharge resistor (DR), output terminals for connection of TO, duplex digital metre (DM) with memory with two data inputs and two control inputs, data display (DD), clock driver (CD) and control unit (CU) with START and RESET outputs. TVS first output is connected via CS to first output terminal of the device while second TVS output is connected via RR to second output terminal of the device. Discharge switch and reference resistor are connected in series to the device output terminals. DM output is connected with DD input. CD output is connected with DM first control input. Besides, this device comprises extra make and break contacts of CS make contact with DS, peak detector, differentiating element, zero-comparator, light indicator, time counter, voltage multiplier, digital indicator, two scale converters and DM control components. Note also that input terminals of the first scale converter are connected in parallel to the device output terminals. Its output is connected via CS break contact and DS make contact to the first data input of DM and inputs of differentiating elements of peak detector. Differentiating element output is connected to zero-comparator input zero-comparator output being connected to time counter input and light indicator. Time counter output is connected to voltage multiplier first input, multiplier second input being connected to output of peak detector. Voltage multiplier output is connected to input of second scale converter with its output connected to digital indicator input. TVS second output is connected via CS make contact with DM second data input. CD input is connected with control unit START output. DM second control input is connected with DM controls output. Reset inputs of peak detector and those of time counter are connected with RESET output of control unit.

EFFECT: direct measurement of residual life of insulation.

3 dwg

FIELD: electricity.

SUBSTANCE: method is described to measure phase capacitance of an electric network with isolated neutral, which includes alternate measurement of short circuit currents in each phase and differs by the fact that additionally angles are measured between vectors of short circuit currents and vectors of voltages that arise during short circuits on the neutral, using which they calculate phase capacitances.

EFFECT: method increases accuracy and eliminates errors when determining phase capacitances of an electric network.

3 dwg

FIELD: electricity.

SUBSTANCE: poles of an excitation winding are shunted by resistors, some part of which is shunted from time to time with controlled switches for the purpose of changing the state of a measuring circuit; voltages are measured on certain elements of the circuit and insulation resistance is calculated as per the formula given in the invention description. A flow chart of the method includes excitation winding (1); controlled insulation resistance (3); two shunting resistors (6) and (8); two controlled switches (5) and (9) of shunting resistors (6) and (8) respectively; ballast high-ohmic resistors (2) and (4) connected between poles of the excitation winding and switches (5) and (9); switch control unit (10); measuring unit 11; output relay unit (12); control unit (13) of good state of switches; earthing resistor (70). The technical results is achieved by decreasing the level of voltages on the shunting switches by their separation with outputs of the excitation winding by means of high-ohmic resistors, and the switches themselves for control of their good state are connected in parallel to the resistors on which voltages are measured.

EFFECT: improving operating reliability of a control system of the good state of insulation and relay protection of excitation circuits.

2 dwg

FIELD: electricity.

SUBSTANCE: in the intervals between measurements of insulation resistance they control measurement channels by connecting inputs of the first measurement channel to a single point and determining the mean value of "zero" after "n" measurements to account in the calculation of voltage and then connect these same inputs to both poles of the controlled circuit for the subsequent calculation of the ratio of secondary (from "n") values, which are for the second channel to the average value of the first channel, the output calculated indicators beyond preset thresholds conclude inappropriate functioning of the measurement channels, and otherwise the subsequent calculation of the total resistance of insulation is according to the formula:.

EFFECT: improving immunity and measurement accuracy simplification of a device using the claimed method, enhanced functionality through implementation of self-test function of channels and devices in general.

FIELD: measurement equipment.

SUBSTANCE: investigated circuits are grouped into a 2D matrix made of m lines and n columns. Then the groups of circuits making lines and columns of the matrix are in turns connected to a source of DC voltage U via a metering resistor R1, and they perform measurements of voltages ΔU on the resistor R1. Resistances of insulation in groups of circuits are determined according to the formula Rins=R1×(U/ΔU-1). Each investigated circuit participates in two measurements: first within a group of matrix line, and then within a group of matrix column. On the basis of analysis of measurement results they determine circuits with lower resistance of insulation relative to the body. Generation of commands, measurement of voltages, calculation of insulation resistances and formation of control results is done with the help of the software module. For (m×n) investigated circuits it is required to perform (m+n) measurements.

EFFECT: reduced number of switching elements that are responsible for connection of the circuits to a measurement channel, and reduction of time spent for performance of measurements.

2 cl, 1 dwg

FIELD: measurement equipment.

SUBSTANCE: measuring loop is connected between one of the poles of the controlled circuit and an earth bus, the loop comprises a regulated addtional DC source forming unipolar two-stage voltage; in order to decrease measuring voltage of the additional source a pole of the additional source which is like the connected pole of the controlled circuit is connected to the earth circuit. The device comprises a measuring loop connected between one of the poles of the controlled circuit and the earth bus and consisting of a regulated additional DC source, limiting resistors and a current shunt, it also includes a microprocessor element, a precision element to regulate supply voltage at the analogous part of the microprocessor element, a unit to transfer the measurement data; herewith a circuit of zoom operational amplifiers connected in series is connected parallel to the current shunt, one more operational amplifier with input voltage divider is connected parallel to the additional source, outputs of the operational amplifiers are connected to the inputs of analogous-digital conversion of the microprocessor element, and the microprocessor element output regulating the additional source has the function of pulse-duration modulation.

EFFECT: improvement of accuracy and credibility of measurements.

2 cl, 1 dwg

FIELD: measurement equipment.

SUBSTANCE: in the method to measure resistance of insulation and to protect against short circuits to a body in power circuits of diesel locomotives, based on connection of a circuit of two serially connected resistors to poles of a DC circuit, in the place of resistor connection to each other there are some ends of two measurement circuits connected, the first measurement circuit comprises a resistor, a voltage sensor and diode. The second measurement circuit comprises the second resistor, the second voltage sensor and the second diode connected in polarity, which is reverse relative to the first measurement circuit, other ends of the first and second measurement circuits are connected to the grounding element. In process of measurement they measure voltage drops at resistors in the first and second measurement circuits. Voltage is measured at poles of the DC circuit. On the basis of these parameters they calculate resistance of insulation separately in a positive circuit and separately in a negative circuit, and if one of these resistances drops down to the specified threshold value, it is assumed there was a breakthrough of insulation in the appropriate circuit, and the decision is made to implement protection by removal of excitation off a generator, which supplies to the power circuit of the diesel locomotive.

EFFECT: increased reliability and stability of the method due to monitoring of condition of insulation resistance in power circuits of diesel locomotives under continuously alternating voltage with simultaneous permanent realisation of protection against insulation breakthrough to a body.

1 dwg

FIELD: domestic appliances.

SUBSTANCE: proposed plug primarily designed for computers having three-conductor cord of which one is ground conductor, and also for connecting and grounding domestic appliances in apartments provided with standard two-contact receptacles and having no European-type ground-contact ones is, essentially, standard plug with two thin pins whose shroud accommodates resistor; one of resistor leads is connected to plug pin meant for further connection to one of receptacle jacks connected to neutral wire of supply mains. Other resistor lead is used for connecting ground conductor of three-conductor cord of electrical appliance; it has miniature neon lamp one of whose leads is connected to metal contact installed on plug shroud and other lead, to resistor lead used for connecting ground conductor of electrical appliance cord; resistor is dual-function device used to connect electrical appliance to ground and to limit current through neon lamp; plug shroud has peephole to check lamp for glow upon touching metal contact with finger.

EFFECT: improved performance characteristics, enlarged functional capabilities.

1 cl, 1 dwg

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