Method of searching for damages in underground pipe insulation
SUBSTANCE: electrical currents are generated on two sides of the analysed section of a pipe. Movement is carried out on the pipeline route from a receiver with a magnetic field strength sensor. In the initial position, the magnetic axis of the sensor lies in the vertical plane passing through the axis of the pipe. Signals generated by components of magnetic field strength components in the given plane from both currents in the receiver are equal to zero. During movement, equality to zero of the signal from the current on one side of the pipe is constantly monitored through rotation about the vertical axis of the receiver. The point of damage to insulation is found from the signal in the receiver from the vector sum of magnetic field strength values generated by current on the other side of the pipe section and stray current from it.
EFFECT: efficient detection and accuracy of locating damages and reduced labour input.
The invention relates to a method of fault isolation of pipelines, cables and other underground utilities.
The known method for the contactless detection of insulation, in which the seeker insulation containing two transducer of the magnetic field into an electrical signal, is placed over interstate communication on vertical straight to the track so that the first placed under the second set alternately in places of control along the route communications. So produce a measurement of the output voltages from the sensors, which are proportional to the intensities azimuthally components of the magnetic field created by electric current flowing through communication, and using electronic Converter to calculate the depth of communication and the amount flowing through it current. The difference between the current measured in the areas of control, determines the amount of leakage current in the ground at the site of communication (USSR author's certificate N 1592810, G01R 31/08, 1987).
The main disadvantage of this method is the low performance.
Closest to the proposed method is a method for the contactless measurement of the leakage current at the site of underground conductors line, whereby when moving along the conductors on its phase is created with each of the two sides of the modulated electric current. At two points at the beginning and at two points at the end of the subject site, and the points at the beginning and at the end of the segment are the same distance from each other along straight, which is a continuation of the radii of communication, the receiver containing the magnetic field sensors to measure tension azimuthally components of the magnetic fields created by these currents. The detection of a leakage current from the modulated currents are, in defining the beginning and end of the segment against the tension azimuthally component of the magnetic field created one of the modulated currents to tension azimuthally component of the magnetic field created by another shock. The equality of these relationships means an absence of leakage currents (RF Patent N2150710, G01R 31/08, 31/02, 1999).
The main disadvantage of this method is the low performance because to determine where insulation is necessary to conduct several measurements, reducing the distance between the two measuring points on the pipeline route.
The proposed method aims at improving the efficiency of the detection and accurate localization of insulation while reducing complexity.
This goal is achieved by creating two sides of the pipeline electric currents moving along the pipeline route with primn the com, containing the sensor magnetic field strength, the magnetic axis is in the initial position lies in a vertical plane passing through the axis of the pipeline, and the signals generated by components of the magnetic field in the plane of both currents in the receiver is equal to zero. When driving along the pipeline to continually provide rotation about the vertical axis of the receiver is equal to zero signal current from one side of the pipeline. When passing over the defect receiver rotate around a vertical axis so as to obtain a zero signal from the vector sum of magnetic fields generated by current from one side of the pipe and the leakage current from it, and place the insulation to find the signal in the receiver from the vector sum of the magnetic fields created by another current, and leakage current from it. The electrical currents that are generated on both sides of the pipeline can have a different frequency.
Figure 1 shows an illustration of the proposed method, and figure 2 is a vector diagram of the magnetic fields generated by currents flowing in the pipeline, and leakage current.
The drawings indicated: insulated pipe 1; the receiver 2 with the magnetic field sensor 3; I1- electric current in the pipeline that is created on one side of the pipelines is a; I2- electric current in the pipeline, created on the other side of the pipeline; I1U- leakage current from the current I1; I2U- leakage current from the current I2; H1the magnetic field created by the current I1; N2the magnetic field created by the current I2; H1Uthe magnetic field created by the current I1U; H2Uthe magnetic field created by the current I2U; H1Sthe magnetic field is a vector sum of H1and H1U; H2Sthe magnetic field is a vector sum of H2and H2UMagnetic axis (AB) sensor in the initial position lies in a vertical plane passing through the axis of the pipe, and the sensor signals from both of the currents in the absence of defect zero. When driving along the pipeline to continually provide rotation about the vertical axis of the receiver is equal to zero signal current from one side of the pipeline. If there is a defect isolation current I1and the leakage current I1Ucreate a magnetic field intensity vector which are added, and the resultant magnetic field H1Slies in a plane angled to the pipeline. When this receiver is turned around a vertical axis so as to obtain a zero signal DOS is ikaetsya, when the direction of the magnetic axis of the sensor (AB1) perpendicular to the direction of the field H1S. The current flowing on the other side of the pipeline (I2) also has a leak in the defect isolation (I2U). Tensions they create magnetic fields H2and H2Uaccordingly, vector formed. Their vector sum of H2Slies in a plane angled to the pipeline and at an angle to the magnetic field H1S. In this regard, when the rotation sensor in the receiver receive the signal from the magnetic field strength H1S. On this signal to find the location of the defect.
As an example, the fault isolation of the pipeline with a diameter of 1420 mm, lying at a depth of 2 m On the section of the pipeline serves the currents on the one hand with a frequency of 10 Hz, and on the other hand - with a frequency of 6.25 Hz. The operator, having a receiver with a flux-gate magnetic field sensor, moves along the pipeline. In the initial position of the magnetic axis of the sensor lies in a vertical plane passing through the axis of the pipeline. When driving along the pipeline operator constantly provides rotation about the vertical axis of the receiver is equal to zero signal current with a frequency of 10 Hz. When passing over the defect isolation pipe he turns the receiver around the slight pressure from the beginning to the axis so that to obtain a zero signal with a frequency of 10 Hz. The fault isolation, the operator finds on the frequency of 6.25 Hz.
Thus, the present invention can solve the problem of increasing the efficiency of detection and accurate localization of insulation while reducing complexity.
The method of fault isolation of underground pipelines, which consists in creating two sides of the pipeline electric currents moving along the pipeline route with the receiver, containing the sensor magnetic field, characterized in that the magnetic axis of the sensor in the initial position lies in a vertical plane passing through the axis of the pipeline, and the signals generated by components of the magnetic field in the plane of both currents in the receiver is equal to zero, and in the process of moving constantly provide rotation about the vertical axis of the receiver is equal to zero signal current from one side of the pipe under the insulation to find the signal in the receiver from the vector sum of magnetic fields generated by the current on the other side of the pipeline, and the leakage current from it.
SUBSTANCE: detection zone in which the search object is located is exposed to low-frequency electromagnetic and microwave fields. The value of the low-frequency electromagnetic field sufficient for onset of mechanical vibrations of the search object in the detection zone is selected. The microwave signal reflected from the detection zone and modulated by mechanical vibration parametres of the search object is received. The useful signal with frequency Ω is isolated from the received modulated microwave signal, where Ω is frequency of mechanical vibration of the search object. The device has a low-frequency generator connected to an inductive radiator, an autodyne microwave transceiver with an antenna, a phase detector, a low-pass filter and a display.
EFFECT: increased sensitivity and reliability of detection.
2 cl, 2 dwg
SUBSTANCE: pulsed electromagnetic field is excited on the profile under analysis. The overall transient intensity characteristic of the complete electromagnetic field (EMF) is measured in the intervals between pulses of the excitation current. Presence of a hydrocarbon deposit is determined based on comparing the value of the polarisation induced component of the electromagnetic field intensity measured during the intervals between current pulses, with a theoretically calculated value. Further, the value electromagnetic field intensity component arising from the induced polarisation process on a given interval of the linear profile and the background induced polarisation value are measured. The type of hydrocarbon is determined from high or low anomalous of measured induced polarisation parametres relative the background.
EFFECT: more reliable detection hydrocarbon deposits and information content of searching with unambiguous identification the type of hydrocarbons.
SUBSTANCE: magnitude of magnetic field induction vector of the Earth (MFIVE) is synchronously measured using two scalar magnetometres placed on separate gondolas. The gradient of the magnitude of the magnetic field induction vector of the Earth is determined and then integrated on the traversed path. The integration results undergo low-pass filtration. The magnitude of the magnetic field induction vector of the Earth is further measured using two extra scalar magnetometres placed on separate gondolas, towed behind the vessel such that the system of four magnetometres is not in the same plane. Coordinates of the magnetometres are synchronously measured with the magnitude of the magnetic field induction vector of the Earth. During combined processing of the magnetometric data and coordinates of the magnetometres, triorthogonal components of the gradient of the magnitude of the magnetic field induction vector of the Earth are determined, as well as increase in magnitude of the magnetic field induction vector of the Earth relative the initial measurement point.
EFFECT: obtaining more accurate results.
FIELD: measurement equipment.
SUBSTANCE: invention is related to electric survey by method of electric resistance for detection of landslip processes development sections and monitoring of filled structures. Measurements are carried out by method of vertical electric probing along bed, slope and near foot on one and another side of embankment. Capacity and specific resistance of fill material layers are identified. Longitudinal conductivity is calculated to detect sections of drowned clay material. Detected sections are used to arrange transverse geoelectric cuts. Measured relative longitudinal conductivity is detected together with slipping surface of drowned clay material. Water samples are taken on detected drowned sections, water specific electric resistance is measured to identify water mineralisation and identify relative longitudinal conductivity of clay in case of its full saturation. Comparison of measured relative longitudinal conductivity of clay to relative longitudinal conductivity in case of its full saturation helps to identify maximum possible condition for landsliding. In order to investigate dynamics of landslip processes, observations are performed in base stations located in detected drowned areas.
EFFECT: improved efficiency of detection and prediction of sections, which are hazardous from the point of view of landsliding.
3 cl, 4 dwg
FIELD: oil and gas industry.
SUBSTANCE: invention refers to oil and gas industry, particularly to hydraulic break of underground reservoirs required, for example for stimulation of oil or gas inflow into well. The method consists in the below described operations: a particle-target and/or propping agent are introduced into a rupture; further, electromagnetic radiation of from approximately 300 MHz to approximately 100 MHz frequency is emitted into the rupture; a reflected signal from the particle-target is analysed for estimation of rupture geometry. Here is also disclosed the method of estimation of underground rupture geometry including operations, where: the target and/or propping agent are introduced into the rupture; also the particle-target and/or propping agent contain high dielectric ceramic with dielectric constant more or equal approximately to 2; electromagnetic radiation of frequency less or equal to approximately 3 GHz is emitted into the rupture; signal reflected from the particle-target and/or propping agent is analysed for estimation of rupture geometry.
EFFECT: ensuring increased reliability and safety of estimation of rupture geometry of hydraulic break, decreased expenditures for this operation.
27 cl, 1 tbl
FIELD: physics; geophysics.
SUBSTANCE: group of inventions (versions) relates to exploration geophysics, in particular to the systems of equipment for conducting sea geoelectrical exploration and is meant for predicting accumulation of hydrocarbons and other minerals, as well as for studying deep structure of the earth's crust. Proposed is a modular bottom station based on combining a basic module for measuring electromagnetic characteristics of sea bottom rocks with additional modules containing equipment for measuring other parametres of the rocks. The additional modules are fitted by the basic module and a weight. All the recording and power supply systems are accommodated in the basic module and are connected to the other modules via pressure-sealed connectors in the housing of the module, and the modules themselves are fixed on the weight using Kevlar sheets which are fitted with an electrochemical releasing element. The additional modules of the bottom station are modules for magnetic and/or seismic measurements. "Rods" can be fastened at the lower part of the housing of the station and in the initial state they are directed upwards at an angle not less than 15° from the vertical and are held using retainers, which are joined to the releasing element of a hoisting device (HD). The "rods" can be telescopic. In another version of the proposed bottom station, the basic module can be used independently. In that case, a hard conical element "basin", made non-conducting material for example polyethylene, polyurethane etc can be placed between the module and the weight. The basic module can also be connected on a semi-rigid rod to a module for magnetic measurements.
EFFECT: measuring different parametres of sea bottom rocks in a single launch, provision for sensitivity of detectors, which exceeds that of stations with such single type measuring devices, compactness and convenient use.
8 cl, 4 dwg
FIELD: instrument making.
SUBSTANCE: invention relates geophysics, particularly, to electromagnetic LF devices intended for analysing GST. Proposed device comprises two antennas arranged orthogonally and connected to receiver, one of them being installed vertically. Proposed device comprises additionally data processing device and third antenna arranged orthogonally to aforesaid two antennas and connected to aforesaid receiver. The later incorporates transmitter with its output connected to the data processing device input. Transmitter allows transmitting signals comprising data on mutually-orthogonal components Hx, Hy, Hz of natural pulsed electromagnetic Earth field to data processing device the later allows computation of Wzx (x, y)=Hz/Hx and Wzy (x, y)=Hz/Hy, determination of relationship Wzx=F(Δf) and Wzy=F(Δf), where "ДГ" is the range of received frequencies of mutually-orthogonal components Hx, Hy, Hz, from f0 to f and integration of aforesaid relationships Wzx and Wzy.
EFFECT: expanded performances, higher accuracy.
9 cl, 5 dwg
FIELD: physics, measurements.
SUBSTANCE: invention relates to exploration geophysics. In compliance with this invention, bottom stations are installed on sea bottom along the line, i.e. profile, covering the area to be explored to form the observation profile (OP), the said station are spaced 1000 m apart. A ship incorporating a generating dipole is directed through the centre of one of electrode separations, close to the centre of explored area area, perpendicular to OP, to form an excitation profile (EP). The electric field magnitudes picked off the bottom station receiving electrodes are referenced to the centre of distance between the appropriate separations of aforesaid bottom station to form an area system of measurement profiles (MO). A one-dimensional inversion is performed for every MO. Proceeding from the data obtained, a 3D geoelectric model of the medium is constructed in units of specific resistance, or specific resistance and parametres of polarisability. Now, proceeding from their abnormalities it is possible to judge upon the presence of a deposit, its position in plan and depth. The ship can carry out researches both with horizontal generating dipole towed on sea surface, and with vertical or horizontal dipole towed on over sea bottom.
EFFECT: reliable forecasting at depths from 0 to 2000 m and deeper.
9 cl, 2 dwg
FIELD: physics; measurements.
SUBSTANCE: present invention pertains to geophysical methods of prospecting. An electromagnetic field is generated through generation of a pseudorandom bipolar sequence of packets of periodical current pulses in a transmitter coil. The value of the cross-correlation function is calculated for components (time derivative) of magnetic or electric field and the current form, either with zero-time shift ΔT between time-sequences of the cross-correlation function or without it. From the values of the cross-correlation function with increment, equal to the period of the current pulses, the impulse reaction of the geoelectric medium is determined, which in turn is used to determine the structure of the geoelectric medium. From the difference of impulse reactions on the background and in the absence of primary magnetic field, objects are identified depending on their induced magnetisation. The generator of electromagnetic field has a dc current source, a rectifier bridge, controlled generator of pseudorandom sequences of time intervals, synchronised by a stabilised clock-pulse generator, and a transmitter coil connected to a current sensor. Between the DC current source and the transmitter coil, a current switch is connected, synchronised by a stabilised clock-pulse generator. The generator of pseudorandom sequences of time intervals is connected to the stabilised clock-pulse generator through a frequency divider. In the second version, the transmitter coil generates recurrent packets of current pulses, uniformly distributed according to a random law on the time interval occupied by the packet. In the second version of the device, the current switch is connected to the generator of recurrent packets, randomly and uniformly distributed during pulses, which in turn is connected to the stabilised clock-pulse generator through a frequency divider.
EFFECT: increased accuracy of data from electrical prospecting and reduced labour input.
15 cl, 5 dwg
FIELD: physics; measurements.
SUBSTANCE: present invention pertains to electrical prospecting using an electrical resistance technique. The invention can be used chiefly, for detecting tectonically crushed, water permeable rocks, detection of ore-bearing objects, covered by loose formations, studying the spread of industrially contaminated underground water in the geological environment etc. One supply ground connection is put at infinity. In a well, several supply ground connections are arranged at a given distance from each other. These connections are successively connected to a current source. For each connection, the potential drop between receiving ground connections are measured using a measurement grid. The apparent electrical resistance values are determined from the potential drop values. Isolines for electrical resistance for all depths where the supply ground connections are drawn up. Presence and position of geoelectric irregularities is determined from the layout of the isolines. Within the boundaries of the detected irregular regions, one of the receiving ground connections is moved around the other. The potential drop between them is measured. In the direction of the receiving line, at maximum voltage value, the spread of linear-stretched irregularities or the position of local objects with increased electroconductivity can be determined.
EFFECT: increased efficiency of detecting irregularities in the geological environment.
2 cl, 2 dwg
SUBSTANCE: device has an oscillating LC circuit connected to a controlled oscillation frequency generator. The generator is connected through a switch to two resonance frequency memory units which correspond to the measured and unknown lengths of the cable. The resonance frequency memory units are connected to a computer of the unknown cable length on the functional:, where fo is natural frequency of the LC circuit, f1 is resonance frequency corresponding to the measured cable length, fx is resonance frequency corresponding to the unknown cable length to the point of rapture. The unknown length lx is calculated by the computer using the formula: lx = l1·F, where: I1 is the measured cable length corresponding to the resonance frequency f1. The computer is connected to a cable length indicator.
EFFECT: simplification, reduced errors and increased safety.
FIELD: electrical engineering.
SUBSTANCE: proposed system comprises two sets of components to ne mounted on appropriate sides of controlled cable terminals. Note here that first set of components comprises metre of air characteristics in cable sheath, metre of cable control conductor insulance relative to ground, metal sheath current metre, analyser of characteristics of a pair of wires and first switching matrix, while second set of components comprises test signal generator and second switching matrix, as well as data transfer circuit connected with control terminal.
EFFECT: continuous control over air pressure, humidity and temperature in cable sheath, insulance of cable control conductor relative to ground and current in metal sheath, as well as control over electric parametres of any pair of cable wires on request.
SUBSTANCE: current for the fault condition and the condition before fault in all terminal stations is measured. Phase voltage for the fault condition and the condition before the fault is measured in one terminal station of the line of the system. A certain hypothetical fault location is assumed. The distance to the hypothetical fault locations and resistance at the point of fault are calculated. The actual point of fault is selected through a first comparison of numerical values of distance to hypothetical fault locations and by dropping those results whose numerical values are negative or greater than one in relative units, and then by analysing calculated values of resistance at the point of fault and dropping those results whose fault resistance is negative. If there is still more than one value which is not dropped from the calculation results, a fair result is selected by analysing values of calculated corresponding impedance values of equivalent sources.
EFFECT: possibility of determining the point of fault for a system with passive and with active branches, resistance to conditions before the fault.
17 cl, 19 dwg
FIELD: electrical engineering.
SUBSTANCE: faulty grounding section is defined, the closest among all such sections to measurement point for which sum of condensance of positive sequence and condensance of return-to-Earth circuit and condensance of positive sequence and condensance of return-to-Earth circuits, if any, between measurement point and such section exceeds or is equal to certain condensance in faulty circuit. Distance between measured point and faulty points is measured proceeding from condensance values and section lengths.
EFFECT: higher accuracy of pinpointing faulty phase grounding for irregular power lines without increasing computing capacities.
9 cl, 4 dwg
FIELD: electrical engineering.
SUBSTANCE: current Ie flowing through tower to ground and voltage Ue at tower relative to ground are measured simultaneously. Symptoms of faults of two types are revealed at the tower and signal about fault is generated: at Ie>0 and Ue≤Uph signal about single-phase earthing, at Ie=0 and Ue.stand.<Ue≤Uph signal about single-phase tower frame ground connection and earthing circuit fault, where Ue.stand. is normalised voltage at tower relative to ground; Uph is circuit phase voltage. Particular tower fault is locally recorded and be remote means at dispatcher control station. Note here that fault signal is converted into encoded signal that comprises fault type sign and tower registration number. Said signal is transmitted via communication or radio line. Signal is decoded and fault is registered. Measured current and voltage are also used for calculation of actual tower earthing resistance. In case actual earthing resistance exceeds normalised value signal is generated indicating said fact, tower earthing circuit fault is registered locally and by remote means.
EFFECT: higher validity of pinpointing faulty tower with single-phase short circuits and control over actual tower earthing resistance.
SUBSTANCE: centre of local control is placed in the beginning of the line, which consists of microprocessor unit, device of communication with dispatcher point, electric circuit transmitter of commands and sensor of instant power. Each receiver of commands has its unique address, receives and follows only those commands from power supply line, which contain its address. To detect faulty load, first commands are sent for disconnection of all loads from power supply line. Then command is sent for connection of a separate load. Power consumed by the line is measured and compared. If power measured does not correspond to the one specified earlier, this load is considered to be faulty, address of this load is transmitted with the help of communication device to dispatcher station, then command is sent for disconnection of this load from power supply line, then process is repeated serially for all line loads.
EFFECT: expansion of functional capabilities.
FIELD: measurement technique.
SUBSTANCE: invention refers to instrumentation technique with protection elements and can be used to record partial discharges incepted in insulation of high-voltage power equipment and to determine their level. Offered device for monitoring discharge processes in high-voltage power equipment contains four transmitting devices and receiving-analysing device. Each transmitting device includes piezoelectric sensor, pre-amplifier, radiomodule with antenna, detector of acoustic signal level, analog-to-digital converter, reference voltage unit, control unit and power supply unit. Receiving-analysing device contains transceiving module with radio antenna, unit for control of discharge process monitoring modes, unit for determination of data transmission channel number, event memory unit, unit for perceiving initial signs of discharge process, unit for comparing patterns of discharge process, library of discharge process patterns, unit for signal shape analysis and data display and signalisation unit.
EFFECT: improvement of quality of acoustic signal from partial discharges incepted in high-voltage equipment insulation analysis.
2 cl, 2 dwg
SUBSTANCE: test points, whose panels are connected to measuring cables, are fitted along the cable run at a certain distance from each other at points for connecting factory lengths of the cable. The route is periodically detoured and measurements are taken by connecting to measuring cables on the panels of the test points (TP). Moisture sensors are fitted in channels of the intercity cable duct line next to viewing devices, with measuring cables on the panels of the test points connected to the said sensors. By connecting panels of the test points through the measuring cables to the moisture sensors, the moisture level is measured, from which air tightness of the channel of the intercity cable duct line is determined.
EFFECT: more efficient monitoring of air tightness.
FIELD: metering equipment.
SUBSTANCE: invention is related to metering equipment and is aimed at expansion of application field. This result is provided due to the fact that in process of monitoring over tightness in channels of international cable ductwork of fibre optic line for transmission to optic fibre with specified interval, fibre optic moisture meters are connected serially, characteristic of back scattering in this optic fibre is measured at one of its ends, and its variances in sections that correspond to areas of fibre optic detectors location are used to assess moisture in areas adjacent to detectors. At the same time in sight devices of internal cable ductwork of fibre optic transmission line, from connecting couplings of optical communication cable, optical fibre of optic communication cable is taken out, where fibre optic moisture detectors are connected, which are placed in channels of international cable ductwork of fibre optic transmission line from the side of sight devices, then characteristic of this optic fibre back scattering is measured in optical communication cable from one of its ends, and its variances are used to monitor tightness of channels in international cable ductwork of fibre-optic transmission line.
EFFECT: expanded field of application.
SUBSTANCE: zero sequence currents without their own measurement and according selection of setpoints serve as monitored electric values, and only direction of supplying feeder current serves as basic parametre, which in its turn increases noise immunity. Continuous monitoring of zero sequence current condition in units, timely selective detection and disconnection of damaged point make it possible to avoid double earth faults. For practical realisation of suggested single-phase earth fault protection method, it is possible to use available devices and functional elements. Operations of measurement, multiplication with further integration, signal coding, information exchange with adjacent units, control of switches may be realised in a comparably simple manner with the help of microprocessor devices. It makes it possible at comparably low material expenses to provide for reliable, selective and fast-acting network protection against single-phased earth fault.
EFFECT: improved reliability of protected network operation.
3 dwg, 2 cl
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