WO2019148794A1 - Method and apparatus for partial discharge detection of high-voltage cable - Google Patents

Method and apparatus for partial discharge detection of high-voltage cable Download PDF

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Publication number
WO2019148794A1
WO2019148794A1 PCT/CN2018/100091 CN2018100091W WO2019148794A1 WO 2019148794 A1 WO2019148794 A1 WO 2019148794A1 CN 2018100091 W CN2018100091 W CN 2018100091W WO 2019148794 A1 WO2019148794 A1 WO 2019148794A1
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WIPO (PCT)
Prior art keywords
signal
partial discharge
distance
detection structure
cable
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PCT/CN2018/100091
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French (fr)
Chinese (zh)
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席菲菲
李国超
李高峰
夏荣
刘弘景
李伟
周峰
Original Assignee
重庆泰山电缆有限公司
国网北京市电力公司
山东电工电气集团有限公司
国家电网有限公司
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Application filed by 重庆泰山电缆有限公司, 国网北京市电力公司, 山东电工电气集团有限公司, 国家电网有限公司 filed Critical 重庆泰山电缆有限公司
Publication of WO2019148794A1 publication Critical patent/WO2019148794A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
    • G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
    • G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
    • G01R31/1272—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation of cable, line or wire insulation, e.g. using partial discharge measurements

Definitions

  • the present disclosure relates to the field of power technology, but is not limited to the field of power technology, and in particular, to a method and apparatus for detecting partial discharge of a high voltage cable.
  • the high-voltage cable partial discharge positioning method mainly adopts the time domain reflection method of the high-frequency current transformer.
  • a serious problem in this method is that when the cable is tested, due to the complicated environment and serious on-site interference, the cable partial discharge signal is a high-frequency signal, the detection signal has small sensitivity, large interference, and serious transmission attenuation characteristics on the long cable transmission. Therefore, the time domain reflection method is used for positioning of the long cable partial discharge, and the positional information cannot be located; or the position information obtained by the local positioning is not accurate.
  • the present disclosure provides a method and apparatus for detecting a partial discharge position of a cable.
  • Embodiments of the present disclosure provide a method for detecting partial discharge of a high voltage cable, including the following steps:
  • the partial discharge signals received by the two detection structures are:
  • X1(t) is the partial discharge signal received by the first detection structure at time t;
  • S1(t, r1) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • X2(t) is the partial discharge signal received by the second detection structure at time t;
  • S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • the correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
  • X1(t) is the partial discharge signal received by the first detection structure at time t;
  • X2(t+ ⁇ ) is the partial discharge signal received by the second detection structure at time t+ ⁇ ;
  • V is the transmission speed of the PD signal in the cable
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t+ ⁇ , r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t+ ⁇ , r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of the noises n1(t) and n2(t) is suppressed to obtain (8);
  • the correlation function of the two PD signals of S1 and S2 is a special function.
  • (Singer function) is composed of a product of a constant factor k0; the maximum value of the Singer function is:
  • r1 is the distance of the first detection structure from the partial discharge point
  • R2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • r1 is the distance of the first detection structure from the partial discharge point
  • R2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • Embodiments of the present disclosure provide a high voltage cable partial discharge detecting device, including:
  • the partial discharge signals received by the two detection structures are:
  • X 1 (t) is the partial discharge signal received by the first detection structure at time t;
  • S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
  • n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • r 1 is the distance of the first detection structure from the partial discharge point
  • X2(t) is the partial discharge signal received by the second detection structure at time t;
  • S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • a first determining module configured to determine a maximum correlation delay time ⁇ m of obtaining two sets of partial discharge signals
  • the correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
  • X1(t) is the partial discharge signal received by the first detection structure at time t;
  • X2(t+ ⁇ ) is the partial discharge signal received by the second detection structure at time t+ ⁇ ;
  • V is the transmission speed of the PD signal in the cable
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t+ ⁇ , r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
  • r 1 is the distance of the first detection structure from the partial discharge point
  • S 2 (t + ⁇ , r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 ⁇ from the partial discharge distance r 2 ;
  • r 2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
  • r 1 is the distance of the first detection structure from the partial discharge point
  • r 2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • a second determining module determines a position of the partial discharge point, wherein, according to formula (13),
  • r 1 is the distance of the first detection structure from the partial discharge point
  • r 2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • FIG. 1 is a flow chart of a method in an embodiment of the present disclosure.
  • Figure 2 is a schematic diagram of partial discharge detection of a cable.
  • FIG. 3 is a schematic cross-sectional view of a partial discharge detecting structure.
  • FIG. 4 is a schematic view showing a partial discharge detecting structure.
  • FIG. 5 is a schematic diagram of a partial discharge detecting structure in an embodiment of the present disclosure.
  • FIG. 6 is an equivalent circuit diagram of a partial discharge detecting structure in an embodiment of the present disclosure.
  • FIG 7 is an electrical schematic diagram of partial discharge detection in an embodiment of the present disclosure.
  • FIG. 8 is a flow chart of a denoising system implementing a partial discharge detecting structure in a specific embodiment of the present disclosure.
  • an embodiment of the present disclosure provides a partial discharge detection method for a high voltage cable, including:
  • the cable partial discharge detecting structures IJ1 and IJ2 are arranged at the first and last joints on the cable transmission line; the partial discharge signals received by the two detecting structures connected to IJ1 and IJ2 are:
  • the partial discharge detection structure is regarded as a point to consider the distance from the partial discharge point;
  • X 1 (t) is the partial discharge signal received by the first detection structure at time t;
  • S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
  • n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • r 1 is the distance of the first detection structure from the partial discharge point
  • X 2 (t) is the partial discharge signal received by the second detection structure at time t;
  • S 2 (t, r 2 ) is a signal observation obtained by the second detection structure at a distance t 2 from the partial discharge distance r 2 ;
  • n 2 (t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • r 2 is the distance of the second detection structure from the partial discharge point
  • the correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
  • X 1 (t) is the partial discharge signal received by the first detection structure at time t;
  • X 2 (t+ ⁇ ) is the partial discharge signal received by the second detection structure at time t+ ⁇ ;
  • V is the transmission speed of the PD signal in the cable
  • T is the signal period
  • S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
  • n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • r 1 is the distance of the first detection structure from the partial discharge point
  • S 2 (t, r 2 ) is a signal observation obtained by the second detection structure at a distance t 2 from the partial discharge distance r 2 ;
  • n 2 (t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • r 2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
  • n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • r 1 is the distance of the first detection structure from the partial discharge point
  • S 2 (t + ⁇ , r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 ⁇ from the partial discharge distance r 2 ;
  • n 2 (t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • r 2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
  • r 1 is the distance of the first detection structure from the partial discharge point
  • S 2 (t + ⁇ , r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 ⁇ from the partial discharge distance r 2 ;
  • r 2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
  • the correlation function of the two PD signals of S1 and S2 is a special function.
  • (Singer function) is composed of a product of a constant factor k0; the maximum value of the Singer function is:
  • r 1 is the distance of the first detection structure from the partial discharge point
  • r 2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • r 1 is the distance of the first detection structure from the partial discharge point
  • r 2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • Calculating the horizontal distance between the local discharge and the first detection result is equivalent to locating the position of the partial discharge point.
  • the present disclosure can not suppress the noise at both ends of the detection impedance due to the noise signal from the wire core, so that the noise can be well suppressed, and since the metal foil such as the aluminum casing is connected to the outer screen layer, the external noise is not Entering the amplifier through the signal input, this better suppresses the local environmental noise, thus achieving accurate positioning of the partial discharge position.
  • a detection structure for partial discharge of the cable is provided at each of the two ends of the cable transmission.
  • the partial discharge here may include: abnormal discharge of an abnormal point such as a breakage or a gap of the cable transmission line. Since the abnormal discharge discharges part of the electric energy on the cable transmission line, it is called in the embodiment of the present disclosure: Partial Discharge.
  • the partial discharge detection structure is disposed within a predetermined distance of the end of the cable transmission line, for example, within 1 meter.
  • the cable partial discharge detecting structure includes a first cable 1 and a second cable 2; the first cable 1 and the second cable 2 are connected by a joint 3; the first cable 1
  • the outer surface of the outer screen layer near the joint 3 is provided with a first metal foil 4; the outer surface of the outer layer of the second cable 2 near the joint 3 is provided with a second metal foil 5; the first metal foil 4 and the second metal foil
  • the electrical connection between the five has a detection impedance of 6; in the present case, the metal foil is preferably made of copper foil, and in other schemes, a similar metal may be used to achieve the specific function of the metal.
  • An insulating cylinder 3a is disposed in the joint 3; the metal shield 7 of the first cable 1 and the second cable 2 is disconnected through the insulating cylinder 3a.
  • the noise signal from the wire core Due to the noise signal from the wire core, no voltage drop can be generated at both ends of the detection impedance, so that the noise can be well suppressed, and since the metal foil such as the aluminum casing is connected to the outer screen layer, the external noise does not pass the signal.
  • the input enters the amplifier, which better suppresses the ambient noise and enables accurate positioning of the partial discharge position.
  • the cable transmission line is not composed of a single cable that is completed at the time of shipment, but requires multiple cables to be connected. Therefore, if a cable transmission line is composed of multiple cables, An intermediate connector is provided on the circuit transmission line. In this embodiment, if there is an intermediate joint on the cable transmission line; the metal shield layer 7 of the cable on both sides of the conventional cable intermediate joint is connected as an integral structure.
  • step 1) the noise of the partial discharge signal is removed using the following steps:
  • the signal outputted in the step 14) is judged based on the frequency of occurrence of the discharge pulse signal as a partial discharge signal and output.
  • step 13 the frequency selective amplification of the signal is performed according to the following steps:
  • the first joint IJ1 is selected according to the first joint IJ1 PD signal detection range and the adjacent intermediate joint NJ PD signal frequency range;
  • the tail joint IJ2 is selected according to the tail joint IJ2 partial discharge signal detection range and the frequency range of the adjacent intermediate joint NJ PD signal.
  • the center frequency of the first joint IJ1 PD signal is set at the frequency suitable for detecting the IJ1 intermediate joint PD signal, and the tail joint IJ2 is selected according to the tail joint IJ2 PD signal detection range and the intermediate connector NJ PD signal frequency range. frequency.
  • the frequency selection is performed by the following range of center frequencies:
  • the center frequency range of the H signal can be set to 50 MHz - 300 MHz; the center frequency of the signal L is set at a frequency suitable for detecting the adjacent NJ intermediate connector PD signal, preferably, the center frequency of L
  • the range can be set to 1MHZ----50MHZ; the center frequencies of signals H and L are different, and h, l is the signal to which the antenna is coupled, after the corresponding frequency-amplified signal.
  • the frequency range of the partial discharge detecting structure is different, and the technical effect of the present disclosure can also be achieved after the central frequency range of the signal between H and L is changed accordingly.
  • the partial discharge detecting mechanism is respectively installed near the two sides of the cable intermediate joint, and the first metal foil 4 or the second metal foil 5 and the cable core wire respectively form a capacitance between the two metal foil outputs.
  • Connect the sense impedance eg 50 ohm resistor.
  • the impedance is collected to collect the signal collected by the PD signal on the two built-in capacitive sensors. This signal is differentially amplified by the amplifier (as shown in Figure 7), processed by the A/D conversion input computer or input to the oscilloscope for display.
  • Rc is the characteristic impedance of the cable
  • C is the capacitance between the wire core and the copper foil of the capacitance sensor
  • Cs is the stray capacitance between the capacitive coupler and the metal shield
  • Rs is the capacitive coupler The resistance between the copper foil and the shielding layer
  • Rf is the input impedance of the measuring unit
  • C1 is the capacitance between the first metal foil 4 and the cable
  • C2 is the capacitance between the first metal foil 4 and the cable.
  • the detection loop of the differential method is similar to the differential balance circuit.
  • the noise signal from the wire core can not generate a voltage drop at both ends of the sense impedance, so the noise can be well suppressed. Since the aluminum casing is connected to the outer screen layer, external noise does not enter the amplifier through the signal input terminal, which better suppresses the on-site environmental noise.
  • the partial discharge detection signal at the first joint IJ1 and the first antenna T1 coupling signal are frequency-selectively amplified, and the partial discharge detection signal at the tail joint IJ2 and the second antenna T2 coupling signal are frequency-selectively amplified.
  • the center frequency of the signal H is set at a frequency suitable for detecting the IJ intermediate joint PD signal
  • the center frequency of the signal L is set at a frequency suitable for detecting the adjacent NJ intermediate joint PD signal
  • the signals H and L The center frequencies are different, and h, l are the signals to which the antenna is coupled.
  • the amplified signal is modulated and transmitted to the monitoring station through the optical fiber, and the return signal is demodulated at the far end.
  • the function of the noise gate in the figure is to compare the signal detected by the partial discharge detection structure with the noise signal coupled to the antenna, and treat the corresponding signals in the two as noise signals and reject them.
  • the function of the continuous gate is to determine whether it is a partial discharge signal and output the signal according to the frequency of occurrence of the discharge pulse signal.
  • the function of the NJ gate is to match the SL1 signal and the SL2 signal respectively outputted by the noise gates on both sides of IJ1 and IJ2, and to treat the signals corresponding to the SL1 signal and the SL2 signal as partial discharge pulses SL and output them.
  • the function of the selection switch is to select the three signals IJ1, IJ2, and NJ to output to the A/D switch; this processing can reduce the processing circuit cost.
  • the computer can perform calculation according to the method provided by the present disclosure and output the coordinates of the PD.
  • the center frequency of the signal H is set at a frequency suitable for detecting the IJ intermediate joint PD signal.
  • the center frequency range of the H signal can be set to 50 MHz---300 MHz; the center frequency of the signal L is set to be suitable for detection.
  • the frequency of the adjacent NJ intermediate connector PD signal is better, the center frequency range of L can be set to 1MHZ----50MHZ; the center frequencies of signals H and L are different, and h, l is the antenna.
  • the coupled signal passes through the corresponding frequency-amplified signal.
  • the frequency range of the partial discharge detecting structure is different, and the technical effect of the present disclosure can also be achieved after the central frequency range of the signal between H and L is changed accordingly.
  • the embodiment of the invention provides a high voltage cable partial discharge detecting device, comprising:
  • the partial discharge signals received by the two detection structures are:
  • X 1 (t) is the partial discharge signal received by the first detection structure at time t;
  • S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
  • n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • r 1 is the distance of the first detection structure from the partial discharge point
  • X2(t) is the partial discharge signal received by the second detection structure at time t;
  • S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • a first determining module configured to determine a maximum correlation delay time ⁇ m of obtaining two sets of partial discharge signals
  • the correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
  • X1(t) is the partial discharge signal received by the first detection structure at time t;
  • X2(t+ ⁇ ) is the partial discharge signal received by the second detection structure at time t+ ⁇ ;
  • V is the transmission speed of the PD signal in the cable
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
  • N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure
  • R1 is the distance of the first detection structure from the partial discharge point
  • S2(t+ ⁇ , r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
  • N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure
  • R2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
  • r 1 is the distance of the first detection structure from the partial discharge point
  • S 2 (t + ⁇ , r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 ⁇ from the partial discharge distance r 2 ;
  • r 2 is the distance of the second detection structure from the partial discharge point
  • T is the signal period
  • the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
  • r 1 is the distance of the first detection structure from the partial discharge point
  • r 2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • a second determining module determines a position of the partial discharge point, wherein, according to formula (13),
  • r 1 is the distance of the first detection structure from the partial discharge point
  • r 2 is the distance of the second detection structure from the partial discharge point
  • v is the transmission speed of the partial discharge signal in the cable
  • ⁇ m is the maximum correlation delay time of the two groups of partial discharge signals
  • the cable partial discharge detecting structure includes a first cable and a second cable; the first cable and the second cable are connected by a joint; the first cable is adjacent to an outer layer of the joint The outer surface is provided with a first metal foil; the second cable is provided with a second metal foil near the outer surface of the outer layer; the first metal foil and the second metal foil are electrically connected with a detection impedance ;
  • An insulating cylinder is disposed in the joint; the metal shield of the first cable and the second cable is disconnected through the insulating cylinder.
  • An intermediate joint is connected in series between the joints of the two detecting structures; the metal shielding layers of the cables on both sides of the intermediate joint are connected as a unitary structure.
  • the device also includes:
  • the denoising module is used to remove the noise of the partial discharge signal by the following steps:
  • the output signal is judged based on the frequency of occurrence of the discharge pulse signal as a partial discharge signal and output.
  • the second determining module is specifically configured to determine a frequency range suitable for detecting a PD signal of the first connector; determine a frequency range suitable for detecting a PD signal of the tail connector; and determine a frequency of detecting a PD signal of the intermediate connector. Range; the first joint is selected according to the detection range of the first joint PD signal and the frequency range of the adjacent intermediate joint PD signal; the tail joint is in accordance with the tail joint PD signal detection range and the adjacent intermediate joint PD signal The frequency range is selected.
  • a computer storage medium storing computer executable instructions; the computer executable instructions being executable to implement one or more of the aforementioned high voltage cable partial discharge detection methods.
  • the computer storage medium can include: a non-transitory storage medium.
  • the continuous gate, NJ gate, and noise gate circuit can be realized by a relatively conventional circuit.

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Abstract

A method for partial discharge detection of a high-voltage cable, comprising the following steps: 1) obtaining two sets of partial discharge signals on a cable transmission line, cable partial discharge detection structures being provided at first and tail joints on the cable transmission line, an intermediate joint being connected in series between the joints of the two detection structures, and metal shielding layers of cables at two sides of the intermediate joint being connected into an integrated structure; 2) determining the maximum correlation delay time τm for obtaining the two sets of partial discharge signals; and 3) determining a position of a partial discharge point. Also provided are an apparatus for partial discharge detection of a high-voltage cable and a computer storage medium.

Description

高压电缆局部放电检测方法及装置High-voltage cable partial discharge detecting method and device
相关申请的交叉引用Cross-reference to related applications
本申请基于申请号为201810091862.8、申请日为2018年01月30日的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。The present application is filed on the basis of the Chinese Patent Application No. PCT Application No. No. No. No. No. No. No. No. No. No. No. No. Publication No.
技术领域Technical field
本公开涉及电力技术领域但不限于电力技术领域，尤其涉及一种高压电缆局部放电检测方法及装置。The present disclosure relates to the field of power technology, but is not limited to the field of power technology, and in particular, to a method and apparatus for detecting partial discharge of a high voltage cable.
背景技术Background technique
随着经济的快速发展，城市电网的用电量逐年增加，结合城市的美观设计，电力电缆的大量的使用，已成为城市内传输电力的主要产品。由于电缆的绝缘结构设计及现场施工工艺等原因，以及电缆的寿命老化，电缆的绝缘问题越来越多，局部放电(以下简称局放)尤为突出。如果不能及时的检测并处理电缆局放绝缘问题，一旦电缆绝缘击穿就会导致重大停电事故，影响城市的正常运转。因此，对交联聚乙烯电缆的局放检测及定位方法的研究尤为重要。With the rapid development of the economy, the electricity consumption of urban power grids has increased year by year. Combined with the beautiful design of the city, the large-scale use of power cables has become the main product of transmission of electricity within the city. Due to the insulation structure design of the cable and the on-site construction process, as well as the aging of the cable, the insulation problem of the cable is more and more, and the partial discharge (hereinafter referred to as the partial discharge) is particularly prominent. If the cable insulation problem cannot be detected and handled in time, once the cable insulation breakdown, it will cause a major power outage and affect the normal operation of the city. Therefore, research on partial discharge detection and positioning methods for XLPE cables is particularly important.
目前，高压电缆局放定位方法主要采用高频电流互感器的时域反射法。这种方法存在的一个严重问题就是电缆测试时，由于环境复杂，现场干扰严重，电缆局放信号属于高频信号，检测信号灵敏度小，干扰较大，及在长电缆上传输存在严重传输衰减特性，所以用时域反射法在长电缆局放定位上，无法进行局放定位；或者局方定位得到的位置信息不精确。At present, the high-voltage cable partial discharge positioning method mainly adopts the time domain reflection method of the high-frequency current transformer. A serious problem in this method is that when the cable is tested, due to the complicated environment and serious on-site interference, the cable partial discharge signal is a high-frequency signal, the detection signal has small sensitivity, large interference, and serious transmission attenuation characteristics on the long cable transmission. Therefore, the time domain reflection method is used for positioning of the long cable partial discharge, and the positional information cannot be located; or the position information obtained by the local positioning is not accurate.
发明内容Summary of the invention
本公开提供一种可准确定位电缆局部放电位置的检测方法及装置。The present disclosure provides a method and apparatus for detecting a partial discharge position of a cable.
本公开实施例提供了一种高压电缆局部放电检测方法，包括以下步骤：Embodiments of the present disclosure provide a method for detecting partial discharge of a high voltage cable, including the following steps:
1)在电缆传输线路上获得两组局部放电信号，其中，1) obtaining two sets of partial discharge signals on the cable transmission line, wherein
在电缆传输线路上首尾两个接头处设置电缆局部放电检测结构；Providing a cable partial discharge detecting structure at the first and last joints on the cable transmission line;
两个检测结构接收到的局部放电信号分别为：The partial discharge signals received by the two detection structures are:
X1(t)＝S1(t,r1)+n1(t)     (1)X1(t)=S1(t,r1)+n1(t) (1)
X2(t)＝S1(t,r2)+n2(t)     (2)X2(t)=S1(t,r2)+n2(t) (2)
其中，X1(t)为t时刻第一个检测结构接收到的局部放电信号；Where X1(t) is the partial discharge signal received by the first detection structure at time t;
S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；S1(t, r1) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
X2(t)为t时刻第二个检测结构接收到的局部放电信号；X2(t) is the partial discharge signal received by the second detection structure at time t;
S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
2)计算获得两组局部放电信号的最大相关延时时间τ m； 2) Calculate the maximum correlation delay time τ m of the two groups of partial discharge signals;
对式(1)和(2)采用余弦信号进行分析，令信号方程为：The equations (1) and (2) are analyzed using a cosine signal, so that the signal equation is:
S1(t,r1)＝Ui e-ɑ r1cos w0(t-r1/v)    (3)S1(t,r1)=Ui e-ɑ r1cos w0(t-r1/v) (3)
S2(t,r2)＝Ui e-ɑ r2cos w0(t-r2/v)    (4)S2(t,r2)=Ui e-ɑ r2cos w0(t-r2/v) (4)
两个检测结构获得的局部放电信号的观测值的相关函数为：The correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
Figure PCTCN2018100091-appb-000001
Figure PCTCN2018100091-appb-000001
其中，X1(t)为t时刻第一个检测结构接收到的局部放电信号；Where X1(t) is the partial discharge signal received by the first detection structure at time t;
X2(t+τ)为t+τ时刻第二个检测结构接收到的局部放电信号；X2(t+τ) is the partial discharge signal received by the second detection structure at time t+τ;
V为局放信号在电缆中的传输速度；V is the transmission speed of the PD signal in the cable;
Figure PCTCN2018100091-appb-000002
为第一个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000002
The amplitude of the cosine signal received by the first detection mechanism;
Figure PCTCN2018100091-appb-000003
为第二个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000003
The amplitude of the cosine signal received by the second detection mechanism;
-a为衰减因子； -a is the attenuation factor;
T为信号周期；T is the signal period;
将式(1)和(2)代入式(5)可得：Substituting equations (1) and (2) into equation (5) yields:
Figure PCTCN2018100091-appb-000004
Figure PCTCN2018100091-appb-000004
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
假定局放信号和噪声是完全不相干的，(6)可以简化为：Assuming that the PD signal and noise are completely irrelevant, (6) can be simplified as:
Figure PCTCN2018100091-appb-000005
Figure PCTCN2018100091-appb-000005
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t+τ，r2)为t+τ时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t+τ, r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号n 1(t)和n 2(t)完全不相干，那么将局放信号从噪声中分离出来，即： If the noise signals n 1 (t) and n 2 (t) are completely uncorrelated, then the PD signal is separated from the noise, ie:
Figure PCTCN2018100091-appb-000006
Figure PCTCN2018100091-appb-000006
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t+τ，r2)为t+τ时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t+τ, r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号与局部放电信号相干，则对局部放电信号进行去噪处理，压制噪声n1(t)和n2(t)的干扰，得到(8)式；If the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of the noises n1(t) and n2(t) is suppressed to obtain (8);
对式(8)在一个周期进行积分；已知局放信号的周期为
Figure PCTCN2018100091-appb-000007
那么 将式(3)和(4)代入式(8)，经过积分可得： Integrate equation (8) in one cycle; the period of known partial discharge signal is
Figure PCTCN2018100091-appb-000007
Then substituting equations (3) and (4) into equation (8), after integration, you can get:
Figure PCTCN2018100091-appb-000008
Figure PCTCN2018100091-appb-000008
其中：
Figure PCTCN2018100091-appb-000009
among them:
Figure PCTCN2018100091-appb-000009
由(9)可知，S1和S2两个局放信号的相关函数是由一个特殊函数
Figure PCTCN2018100091-appb-000010
(辛格函数)与一个常数因子k0的乘积构成；辛格函数的极大值为： It can be seen from (9) that the correlation function of the two PD signals of S1 and S2 is a special function.
Figure PCTCN2018100091-appb-000010
(Singer function) is composed of a product of a constant factor k0; the maximum value of the Singer function is:
Figure PCTCN2018100091-appb-000011
Figure PCTCN2018100091-appb-000011
所以相关函数的最大值对应着：So the maximum value of the correlation function corresponds to:
Figure PCTCN2018100091-appb-000012
其值趋于0     (11)
Figure PCTCN2018100091-appb-000012
Its value tends to 0 (11)
w0不可能为0，所以：
Figure PCTCN2018100091-appb-000013
W0 cannot be 0, so:
Figure PCTCN2018100091-appb-000013
Figure PCTCN2018100091-appb-000014
Figure PCTCN2018100091-appb-000014
其中，r1为第一个检测结构距离局部放电点的距离；Where r1 is the distance of the first detection structure from the partial discharge point;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
3)确定局部放电点的位置3) Determine the location of the partial discharge point
根据式(13)可得：According to formula (13):
r1＝r2-vτ m    (14) R1=r2-vτ m (14)
其中，r1为第一个检测结构距离局部放电点的距离；Where r1 is the distance of the first detection structure from the partial discharge point;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
设第一检测结构和第二检测结构的距离为D,且r1＝L,则r2＝D-L,可得：Let the distance between the first detection structure and the second detection structure be D, and r1=L, then r2=D-L, and obtain:
L＝D-L-vτ m    (15) L=DL-vτ m (15)
则局放点与第一检测结构的水平距离L为：Then the horizontal distance L between the local discharge point and the first detection structure is:
Figure PCTCN2018100091-appb-000015
Figure PCTCN2018100091-appb-000015
本公开实施例提供一种高压电缆局部放电检测装置，包括：Embodiments of the present disclosure provide a high voltage cable partial discharge detecting device, including:
获得模块，用于在电缆传输线路上获得两组局部放电信号，其中，在电缆传输线路上首尾两个接头处设置电缆局部放电检测结构；Obtaining a module for obtaining two sets of partial discharge signals on the cable transmission line, wherein a cable partial discharge detecting structure is disposed at the first and last joints on the cable transmission line;
两个检测结构接收到的局部放电信号分别为：The partial discharge signals received by the two detection structures are:
X 1(t)＝S 1(t,r 1)+n 1(t)    (1) X 1 (t)=S 1 (t,r 1 )+n 1 (t) (1)
X 2(t)＝S 1(t,r 2)+n 2(t)    (2) X 2 (t)=S 1 (t,r 2 )+n 2 (t) (2)
其中，X 1(t)为t时刻第一个检测结构接收到的局部放电信号； Where X 1 (t) is the partial discharge signal received by the first detection structure at time t;
S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
X2(t)为t时刻第二个检测结构接收到的局部放电信号；X2(t) is the partial discharge signal received by the second detection structure at time t;
S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
第一确定模块，用于确定获得两组局部放电信号的最大相关延时时间 τ m； a first determining module, configured to determine a maximum correlation delay time τ m of obtaining two sets of partial discharge signals;
对式(1)和(2)采用余弦信号进行分析，令信号方程为：The equations (1) and (2) are analyzed using a cosine signal, so that the signal equation is:
S1(t,r1)＝Ui e-ɑ r1cos w0(t-r1/v)     (3)S1(t,r1)=Ui e-ɑ r1cos w0(t-r1/v) (3)
S2(t,r2)＝Ui e-ɑ r2cos w0(t-r2/v)     (4)S2(t,r2)=Ui e-ɑ r2cos w0(t-r2/v) (4)
两个检测结构获得的局部放电信号的观测值的相关函数为：The correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
Figure PCTCN2018100091-appb-000016
Figure PCTCN2018100091-appb-000016
其中，X1(t)为t时刻第一个检测结构接收到的局部放电信号；Where X1(t) is the partial discharge signal received by the first detection structure at time t;
X2(t+τ)为t+τ时刻第二个检测结构接收到的局部放电信号；X2(t+τ) is the partial discharge signal received by the second detection structure at time t+τ;
V为局放信号在电缆中的传输速度；V is the transmission speed of the PD signal in the cable;
Figure PCTCN2018100091-appb-000017
为第一个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000017
The amplitude of the cosine signal received by the first detection mechanism;
Figure PCTCN2018100091-appb-000018
为第二个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000018
The amplitude of the cosine signal received by the second detection mechanism;
-a为衰减因子； -a is the attenuation factor;
T为信号周期；T is the signal period;
将式(1)和(2)代入式(5)可得：Substituting equations (1) and (2) into equation (5) yields:
Figure PCTCN2018100091-appb-000019
Figure PCTCN2018100091-appb-000019
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机 噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
假定局放信号和噪声是完全不相干的，(6)可以简化为：Assuming that the PD signal and noise are completely irrelevant, (6) can be simplified as:
Figure PCTCN2018100091-appb-000020
Figure PCTCN2018100091-appb-000020
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t+τ，r2)为t+τ时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t+τ, r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号n 1(t)和n 2(t)完全不相干，那么将局放信号从噪声中分离出来，即： If the noise signals n 1 (t) and n 2 (t) are completely uncorrelated, then the PD signal is separated from the noise, ie:
Figure PCTCN2018100091-appb-000021
Figure PCTCN2018100091-appb-000021
其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
S 2(t+τ，r 2)为t+τ时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t + τ, r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 τ from the partial discharge distance r 2 ;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号与局部放电信号相干，则对局部放电信号进行去噪处理，压制噪声n 1(t)和n 2(t)的干扰，得到(8)式； If the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
对式(8)在一个周期进行积分；已知局放信号的周期为
Figure PCTCN2018100091-appb-000022
那么将式(3)和(4)代入式(8)，经过积分可得： Integrate equation (8) in one cycle; the period of known partial discharge signal is
Figure PCTCN2018100091-appb-000022
Then substituting equations (3) and (4) into equation (8), after integration, you can get:
Figure PCTCN2018100091-appb-000023
Figure PCTCN2018100091-appb-000023
其中：
Figure PCTCN2018100091-appb-000024
among them:
Figure PCTCN2018100091-appb-000024
由(9)可知，S 1和S 2两个局放信号的相关函数是由一个特殊函数
Figure PCTCN2018100091-appb-000025
(辛格函数)与一个常数因子k 0的乘积构成；辛格函数的极大值为： It can be seen from (9) that the correlation function of the two PD signals of S 1 and S 2 is a special function.
Figure PCTCN2018100091-appb-000025
(Singer function) is composed of a product of a constant factor k 0 ; the maximum value of the singular function is:
Figure PCTCN2018100091-appb-000026
Figure PCTCN2018100091-appb-000026
所以相关函数的最大值对应着：So the maximum value of the correlation function corresponds to:
Figure PCTCN2018100091-appb-000027
其值趋于0     (11)
Figure PCTCN2018100091-appb-000027
Its value tends to 0 (11)
w0不可能为0，所以：
Figure PCTCN2018100091-appb-000028
W0 cannot be 0, so:
Figure PCTCN2018100091-appb-000028
Figure PCTCN2018100091-appb-000029
Figure PCTCN2018100091-appb-000029
其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
第二确定模块，确定局部放电点的位置，其中，根据式(13)可得：a second determining module determines a position of the partial discharge point, wherein, according to formula (13),
r 1＝r 2-vτ m     (14) r 1 =r 2 -vτ m (14)
其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
设第一检测结构和第二检测结构的距离为D,且r 1＝L,则r 2＝D-L,可得： Let the distance between the first detection structure and the second detection structure be D, and r 1 = L, then r 2 = DL, which can be obtained:
L＝D-L-vτ m   (15) L=DL-vτ m (15)
则局放点与第一检测结构的水平距离L为：Then the horizontal distance L between the local discharge point and the first detection structure is:
Figure PCTCN2018100091-appb-000030
Figure PCTCN2018100091-appb-000030
附图说明DRAWINGS
图1是本公开一具体实施方式中的方法流程图。1 is a flow chart of a method in an embodiment of the present disclosure.
图2是电缆局部放电检测示意图。Figure 2 is a schematic diagram of partial discharge detection of a cable.
图3是局部放电检测结构剖面示意图。3 is a schematic cross-sectional view of a partial discharge detecting structure.
图4是局部放电检测结构示意图。4 is a schematic view showing a partial discharge detecting structure.
图5是本公开一具体实施方式中局部放电检测结构的原理图。FIG. 5 is a schematic diagram of a partial discharge detecting structure in an embodiment of the present disclosure.
图6是本公开一具体实施方式中局部放电检测结构的等效电路图。6 is an equivalent circuit diagram of a partial discharge detecting structure in an embodiment of the present disclosure.
图7是本公开一具体实施方式中局部放电检测的电原理图。7 is an electrical schematic diagram of partial discharge detection in an embodiment of the present disclosure.
图8是本公开具体实施方式中实现局部放电检测结构的去噪系统流程图。8 is a flow chart of a denoising system implementing a partial discharge detecting structure in a specific embodiment of the present disclosure.
具体实施方式Detailed ways
下面结合附图和实施例对本公开作进一步说明：The present disclosure will be further described below in conjunction with the accompanying drawings and embodiments:
如图1至图2所示，本公开实施例提供一种高压电缆局部放电检测方法，包括：As shown in FIG. 1 to FIG. 2, an embodiment of the present disclosure provides a partial discharge detection method for a high voltage cable, including:
1)在电缆传输线路上获得两组局部放电信号；如图2，假设局部放电点为o点；1) Obtain two sets of partial discharge signals on the cable transmission line; as shown in Fig. 2, assume that the partial discharge point is o point;
在电缆传输线路上首尾两个接头处设置电缆局部放电检测结构IJ1和IJ2；两个检测结构接IJ1、IJ2收到的局部放电信号分别为：The cable partial discharge detecting structures IJ1 and IJ2 are arranged at the first and last joints on the cable transmission line; the partial discharge signals received by the two detecting structures connected to IJ1 and IJ2 are:
X 1(t)＝S 1(t,r 1)+n 1(t)     (1) X 1 (t)=S 1 (t,r 1 )+n 1 (t) (1)
X 2(t)＝S 1(t,r 2)+n 2(t)     (2) X 2 (t)=S 1 (t,r 2 )+n 2 (t) (2)
由于通常的输送线缆较长，故将局部放电检测结构视为一个点来对其与局部放电点距离进行考虑；Since the usual transmission cable is long, the partial discharge detection structure is regarded as a point to consider the distance from the partial discharge point;
其中，X 1(t)为t时刻第一个检测结构接收到的局部放电信号； Where X 1 (t) is the partial discharge signal received by the first detection structure at time t;
S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
X 2(t)为t时刻第二个检测结构接收到的局部放电信号； X 2 (t) is the partial discharge signal received by the second detection structure at time t;
S 2(t,r 2)为t时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t, r 2 ) is a signal observation obtained by the second detection structure at a distance t 2 from the partial discharge distance r 2 ;
n 2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声； n 2 (t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
2)计算获得两组局部放电信号的最大相关延时时间τ m； 2) Calculate the maximum correlation delay time τ m of the two groups of partial discharge signals;
对式(1)和(2)采用余弦信号进行分析，令信号方程为：The equations (1) and (2) are analyzed using a cosine signal, so that the signal equation is:
S 1(t,r 1)＝Ui e -ɑr1cos w 0(t-r 1/v)     (3) S 1 (t,r 1 )=Ui e -ɑr1 cos w 0 (tr 1 /v) (3)
S 2(t,r 2)＝Ui e -ɑr2cos w 0(t-r 2/v)     (4) S 2 (t,r 2 )=Ui e -ɑr2 cos w 0 (tr 2 /v) (4)
两个检测结构获得的局部放电信号的观测值的相关函数为：The correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
Figure PCTCN2018100091-appb-000031
Figure PCTCN2018100091-appb-000031
其中，X 1(t)为t时刻第一个检测结构接收到的局部放电信号； Where X 1 (t) is the partial discharge signal received by the first detection structure at time t;
X 2(t+τ)为t+τ时刻第二个检测结构接收到的局部放电信号； X 2 (t+τ) is the partial discharge signal received by the second detection structure at time t+τ;
V为局放信号在电缆中的传输速度；V is the transmission speed of the PD signal in the cable;
T为信号周期；T is the signal period;
将式(1)和(2)代入式(5)可得：Substituting equations (1) and (2) into equation (5) yields:
Figure PCTCN2018100091-appb-000032
Figure PCTCN2018100091-appb-000032
其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
S 2(t,r 2)为t时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t, r 2 ) is a signal observation obtained by the second detection structure at a distance t 2 from the partial discharge distance r 2 ;
n 2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声； n 2 (t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
假定局放信号和噪声是完全不相干的，(6)可以简化为：Assuming that the PD signal and noise are completely irrelevant, (6) can be simplified as:
Figure PCTCN2018100091-appb-000033
Figure PCTCN2018100091-appb-000033
其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得 的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
S 2(t+τ，r 2)为t+τ时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t + τ, r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 τ from the partial discharge distance r 2 ;
n 2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声； n 2 (t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号n 1(t)和n 2(t)完全不相干，那么将局放信号从噪声中分离出来，即： If the noise signals n 1 (t) and n 2 (t) are completely uncorrelated, then the PD signal is separated from the noise, ie:
Figure PCTCN2018100091-appb-000034
Figure PCTCN2018100091-appb-000034
其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
S 2(t+τ，r 2)为t+τ时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t + τ, r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 τ from the partial discharge distance r 2 ;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号与局部放电信号相干，则对局部放电信号进行去噪处理，压制噪声n 1(t)和n 2(t)的干扰，得到(8)式； If the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
对式(8)在一个周期进行积分；已知局放信号的周期为
Figure PCTCN2018100091-appb-000035
那么将式(3)和(4)代入式(8)，经过积分可得： Integrate equation (8) in one cycle; the period of known partial discharge signal is
Figure PCTCN2018100091-appb-000035
Then substituting equations (3) and (4) into equation (8), after integration, you can get:
Figure PCTCN2018100091-appb-000036
Figure PCTCN2018100091-appb-000036
其中：
Figure PCTCN2018100091-appb-000037
among them:
Figure PCTCN2018100091-appb-000037
由(9)可知，S1和S2两个局放信号的相关函数是由一个特殊函数
Figure PCTCN2018100091-appb-000038
(辛格函数)与一个常数因子k0的乘积构成；辛格函数的极大值为： It can be seen from (9) that the correlation function of the two PD signals of S1 and S2 is a special function.
Figure PCTCN2018100091-appb-000038
(Singer function) is composed of a product of a constant factor k0; the maximum value of the Singer function is:
Figure PCTCN2018100091-appb-000039
Figure PCTCN2018100091-appb-000039
所以相关函数的最大值对应着：So the maximum value of the correlation function corresponds to:
Figure PCTCN2018100091-appb-000040
其值趋于0     (11)
Figure PCTCN2018100091-appb-000040
Its value tends to 0 (11)
w0不可能为0，所以：
Figure PCTCN2018100091-appb-000041
W0 cannot be 0, so:
Figure PCTCN2018100091-appb-000041
因此，
Figure PCTCN2018100091-appb-000042
therefore,
Figure PCTCN2018100091-appb-000042
其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
Figure PCTCN2018100091-appb-000043
为第一个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000043
The amplitude of the cosine signal received by the first detection mechanism;
Figure PCTCN2018100091-appb-000044
为第二个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000044
The amplitude of the cosine signal received by the second detection mechanism;
-a为衰减因子； -a is the attenuation factor;
3)确定局部放电点的位置，3) Determine the position of the partial discharge point,
根据式(13)可得：According to formula (13):
r 1＝r 2-vτ m     (14) r 1 =r 2 -vτ m (14)
其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
设第一检测结构和第二检测结构的距离为D,且r1＝L,则r2＝D-L,可得：Let the distance between the first detection structure and the second detection structure be D, and r1=L, then r2=D-L, and obtain:
L＝D-L-vτ m    (15) L=DL-vτ m (15)
则局放点与第一检测结构的水平距离L为：Then the horizontal distance L between the local discharge point and the first detection structure is:
Figure PCTCN2018100091-appb-000045
Figure PCTCN2018100091-appb-000045
计算出了所述局放电与第一检测结果的水平距离,就相当于定位出了所述局放点的位置。本公开由于来自导线芯的噪声信号，在检测阻抗上的两端不能产生压降，因而可以很好的抑制噪声，而由于有铝外壳等金属箔与外屏层相接，所以外部噪声不会通过信号输入端进入放大器，这就更好地抑制了现场环境噪声，从而实现局部放电位置的准确定位。Calculating the horizontal distance between the local discharge and the first detection result is equivalent to locating the position of the partial discharge point. The present disclosure can not suppress the noise at both ends of the detection impedance due to the noise signal from the wire core, so that the noise can be well suppressed, and since the metal foil such as the aluminum casing is connected to the outer screen layer, the external noise is not Entering the amplifier through the signal input, this better suppresses the local environmental noise, thus achieving accurate positioning of the partial discharge position.
在本示例中在电缆传输上的两个端头出分别设置了一个电缆局部放电的检测结构。In this example, a detection structure for partial discharge of the cable is provided at each of the two ends of the cable transmission.
此处的局部放电可包括：电缆传输线路出现了破损或缺口等异常点出的异常放电，由于这种异常放电会释放掉电缆传输线上的部分电能，故在本公开实施例中称之为：局部放电。在一些树实施例中，所述局部放电的检测结构，设置在电缆传输线路端头的预设距离内，例如，1米范围内。The partial discharge here may include: abnormal discharge of an abnormal point such as a breakage or a gap of the cable transmission line. Since the abnormal discharge discharges part of the electric energy on the cable transmission line, it is called in the embodiment of the present disclosure: Partial Discharge. In some tree embodiments, the partial discharge detection structure is disposed within a predetermined distance of the end of the cable transmission line, for example, within 1 meter.
如图3，在一些实施例中，步骤1)中，电缆局部放电检测结构，包括第一电缆1和第二电缆2；第一电缆1和第二电缆2通过接头3连接；第一电缆1靠近接头3处外屏层的外表面设置有第一金属箔4；第二电缆2靠近接头3处外屏层的外表面设置有第二金属箔5；第一金属箔4和第二金属箔5之间电连接有检测阻抗6；本案中，金属箔优选地用铜箔，其他方案中，也可以采用类似的金属来实现金属的具体功能。As shown in FIG. 3, in some embodiments, in step 1), the cable partial discharge detecting structure includes a first cable 1 and a second cable 2; the first cable 1 and the second cable 2 are connected by a joint 3; the first cable 1 The outer surface of the outer screen layer near the joint 3 is provided with a first metal foil 4; the outer surface of the outer layer of the second cable 2 near the joint 3 is provided with a second metal foil 5; the first metal foil 4 and the second metal foil The electrical connection between the five has a detection impedance of 6; in the present case, the metal foil is preferably made of copper foil, and in other schemes, a similar metal may be used to achieve the specific function of the metal.
接头3内设置有绝缘筒3a；第一电缆1和第二电缆2的金属屏蔽层7通过绝缘筒3a断开。An insulating cylinder 3a is disposed in the joint 3; the metal shield 7 of the first cable 1 and the second cable 2 is disconnected through the insulating cylinder 3a.
由于来自导线芯的噪声信号，在检测阻抗上的两端不能产生压降，因而可以很好的抑制噪声，而由于有铝外壳等金属箔与外屏层相接，所以外部噪声不会通过信号输入端进入放大器，这就更好地抑制了现场环境噪声，从而能够实现局部放电位置的准确定位。Due to the noise signal from the wire core, no voltage drop can be generated at both ends of the detection impedance, so that the noise can be well suppressed, and since the metal foil such as the aluminum casing is connected to the outer screen layer, the external noise does not pass the signal. The input enters the amplifier, which better suppresses the ambient noise and enables accurate positioning of the partial discharge position.
在一些实施例中，电缆传输线路是并不能由出厂时就完整的单根线缆构成，而是需要多根线缆连接而成，故若一段电缆传输线路是由多根电缆构成的，则会在电路传输线路上设置有中间接头。在本实施例中，若电缆传输线路上有中间接头；常规线缆中间接头两侧电缆的金属屏蔽层7连接为一体结构。In some embodiments, the cable transmission line is not composed of a single cable that is completed at the time of shipment, but requires multiple cables to be connected. Therefore, if a cable transmission line is composed of multiple cables, An intermediate connector is provided on the circuit transmission line. In this embodiment, if there is an intermediate joint on the cable transmission line; the metal shield layer 7 of the cable on both sides of the conventional cable intermediate joint is connected as an integral structure.
如图所示8在一些实施例中，步骤1)中，采用下述步骤去除局部放电信号的噪声：As shown in Figure 8, in some embodiments, in step 1), the noise of the partial discharge signal is removed using the following steps:
11)在首尾两个接头IJ1和IJ2处的电缆局部放电检测结构附近分别设置第一天线T1、第二天线T2；11) respectively providing a first antenna T1 and a second antenna T2 in the vicinity of the cable partial discharge detecting structure at the first and second joints IJ1 and IJ2;
12)将首接头处的局部放电检测信号和第一天线耦合信号进行选频放大，将尾接头处的局部放电检测信号和第二天线耦合信号进行选频放大；12) performing frequency selective amplification on the partial discharge detection signal and the first antenna coupling signal at the first joint, and frequency selective amplification of the partial discharge detection signal and the second antenna coupling signal at the tail joint;
13)将选频放大后的局部放电检测信号与天线耦合信号中对应的信号视为噪声信号并丢弃；13) treating the partial discharge detection signal after the frequency selective amplification and the corresponding signal in the antenna coupling signal as a noise signal and discarding;
14)将首接头处接收到的相邻的中间接头局部放电信号与尾接头处接收到的相邻的中间接头局部放电信号中相对应的信号输出；并将首接头处接收到的该接头局部放电信号直接输出；将尾接头处接收到的该接头局部信号直接输出；14) outputting a signal corresponding to a partial discharge signal of the adjacent intermediate joint received at the first joint and a partial discharge signal of the adjacent intermediate joint received at the tail joint; and receiving the joint at the joint The discharge signal is directly output; the local signal of the joint received at the tail joint is directly output;
15)将步骤14)中输出的信号根据放电脉冲信号出现的频繁程度判断是否为局部放电信号并输出。15) The signal outputted in the step 14) is judged based on the frequency of occurrence of the discharge pulse signal as a partial discharge signal and output.
在一些实施例中，步骤13)中，按照以下步骤进行信号的选频放大：In some embodiments, in step 13), the frequency selective amplification of the signal is performed according to the following steps:
131)确定合适检测首接头IJ1局放信号的频率范围；131) determining a frequency range suitable for detecting the IJ1 PD signal of the first connector;
132)确定合适检测尾接头IJ2局放信号的频率范围；132) determining a frequency range suitable for detecting the IJ2 PD signal of the tail joint;
133)确定合适检测中间接头NJ局放信号的频率范围；133) determining a frequency range suitable for detecting an intermediate joint NJ PD signal;
134)首接头IJ1处按照首接头IJ1局放信号检测范围和相邻的中间接头NJ局放信号的频率范围进行选频；134) The first joint IJ1 is selected according to the first joint IJ1 PD signal detection range and the adjacent intermediate joint NJ PD signal frequency range;
尾接头IJ2处按照尾接头IJ2局放信号检测范围和相邻的中间接头NJ局放信号的频率范围进行选频。The tail joint IJ2 is selected according to the tail joint IJ2 partial discharge signal detection range and the frequency range of the adjacent intermediate joint NJ PD signal.
首接头IJ1局放信号的中心频率设定在合适检测该IJ1中间接头局放信号的频率上，尾接头IJ2处按照尾接头IJ2局放信号检测范围和中间接头NJ局放信号的频率范围进行选频。The center frequency of the first joint IJ1 PD signal is set at the frequency suitable for detecting the IJ1 intermediate joint PD signal, and the tail joint IJ2 is selected according to the tail joint IJ2 PD signal detection range and the intermediate connector NJ PD signal frequency range. frequency.
本实施例中，通过以下中心频率的范围进行选频：In this embodiment, the frequency selection is performed by the following range of center frequencies:
较优的，H信号的中心频率范围可以设置为50MHZ---300MHz；信号L的中心频率设定在合适检测相邻的NJ中间接头局放信号的频率上,较优的，L的中心频率范围可以设置为1MHZ----50MHZ；信号H和L的中心频率各不相同，而h,l则为天线耦合到的信号，经过相应选频放大后的信号。Preferably, the center frequency range of the H signal can be set to 50 MHz - 300 MHz; the center frequency of the signal L is set at a frequency suitable for detecting the adjacent NJ intermediate connector PD signal, preferably, the center frequency of L The range can be set to 1MHZ----50MHZ; the center frequencies of signals H and L are different, and h, l is the signal to which the antenna is coupled, after the corresponding frequency-amplified signal.
在实际应用过程中，由于导电线缆的结构各不相同，局部放电检测结构检测的频率范围各有不同，H和L之间信号的中心频率范围相应进行变化后同样能够实现本公开的技术效果。In the actual application process, since the structure of the conductive cable is different, the frequency range of the partial discharge detecting structure is different, and the technical effect of the present disclosure can also be achieved after the central frequency range of the signal between H and L is changed accordingly. .
如图4至图7，将局放检测机构分别安装在电缆中间接头两侧附近，第一金属箔4或者第二金属箔5与电缆芯线分别之间构成电容，两个金属箔输出之间连接检测阻抗(如50欧电阻)。检测阻抗便收集到局放信号在两个内置电容传感器上采集的信号，此信号经过(如图7中所示的放大器)差分放大，经A/D转换输入电脑处理或者输入示波器进行显示。4 to 7, the partial discharge detecting mechanism is respectively installed near the two sides of the cable intermediate joint, and the first metal foil 4 or the second metal foil 5 and the cable core wire respectively form a capacitance between the two metal foil outputs. Connect the sense impedance (eg 50 ohm resistor). The impedance is collected to collect the signal collected by the PD signal on the two built-in capacitive sensors. This signal is differentially amplified by the amplifier (as shown in Figure 7), processed by the A/D conversion input computer or input to the oscilloscope for display.
其中，图5和图6中，Rc是电缆的特性阻抗；C是导线芯线与电容传感器铜箔间的电容；Cs是电容耦合器与金属屏蔽层间的杂散电容；Rs是电容耦合器铜箔与屏蔽层之间的电阻；Rf是测量单元的输入阻抗；C1是第一 金属箔4与电缆之间的电容；C2是第一金属箔4与电缆之间的电容。In Figure 5 and Figure 6, Rc is the characteristic impedance of the cable; C is the capacitance between the wire core and the copper foil of the capacitance sensor; Cs is the stray capacitance between the capacitive coupler and the metal shield; Rs is the capacitive coupler The resistance between the copper foil and the shielding layer; Rf is the input impedance of the measuring unit; C1 is the capacitance between the first metal foil 4 and the cable; and C2 is the capacitance between the first metal foil 4 and the cable.
研究发现，局放信号频谱在1MHz---300MHz范围内，中心频率在10MHz---20MHz时，性噪比最高。差分法的检测回路类似于差动平衡电路，来自导线芯的噪声信号，在检测阻抗上的两端不能产生压降，因而可以很好的抑制噪声。而由于有铝外壳与外屏层相接，所以外部噪声不会通过信号输入端进入放大器，这就更好地抑制了现场环境噪声。The study found that the PD signal spectrum is in the range of 1MHz---300MHz, and the center-frequency is 10MHz--20MHz, the highest noise-to-noise ratio. The detection loop of the differential method is similar to the differential balance circuit. The noise signal from the wire core can not generate a voltage drop at both ends of the sense impedance, so the noise can be well suppressed. Since the aluminum casing is connected to the outer screen layer, external noise does not enter the amplifier through the signal input terminal, which better suppresses the on-site environmental noise.
如图8，利用这一检测原理，我们除了采用差分法原理检测局部放电脉冲信号外，还采取许多抗干扰措施来提高局部放电的识别技术。其基本原理和流程如图8所示。在首尾接头IJ1、IJ2安装检测装置，首尾接头之间还有中间接头NJ(IJ1、IJ2接头与NJ接头的区别在于：IJ接头内有绝缘筒将两侧金属屏蔽断开；NJ接头内没有绝缘筒，两侧的金属屏蔽是连接在一起的)。并在IJ1、IJ2接头附近分别设置第一、第二天线T1、T2来获取背景噪声信号。As shown in Fig. 8, using this detection principle, in addition to using the differential method principle to detect the partial discharge pulse signal, we also take many anti-interference measures to improve the partial discharge identification technology. The basic principle and process are shown in Figure 8. In the first and last joints IJ1, IJ2 installation detection device, there is also a middle joint NJ between the first and last joints (IJ1, IJ2 joint and NJ joint are different: IJ joint has an insulating cylinder to break the metal shield on both sides; NJ joint is not insulated The tube, the metal shields on both sides are connected together). The first and second antennas T1 and T2 are respectively disposed in the vicinity of the IJ1 and IJ2 connectors to obtain a background noise signal.
将首接头IJ1处的局部放电检测信号和第一天线T1耦合信号进行选频放大，将尾接头IJ2处的局部放电检测信号和第二天线T2耦合信号进行选频放大。The partial discharge detection signal at the first joint IJ1 and the first antenna T1 coupling signal are frequency-selectively amplified, and the partial discharge detection signal at the tail joint IJ2 and the second antenna T2 coupling signal are frequency-selectively amplified.
其中，信号H的中心频率设定在合适检测该IJ中间接头局放信号的频率上，信号L的中心频率设定在合适检测相邻的NJ中间接头局放信号的频率上,信号H和L的中心频率各不相同，而h,l则为天线耦合到的信号。放大后的信号经调制通过光纤传到监控站，在远端经解调还原回电信号。图中噪声门的作用是：对比局部放电检测结构检测到的信号与天线耦合到的噪声信号，将这两者中对应的信号视为噪声信号并予以剔除。持续门的作用是：根据放电脉冲信号出现的频繁程度判断是否为局部放电信号并输出该信号。NJ门的作用是：将IJ1和IJ2两侧经噪声门分别输出的SL1信号和SL2信号进行对应，并将SL1信号和SL2信号相对应的信号视为局部放 电脉冲SL并输出。选择开关的作用是：选择把IJ1，IJ2，NJ这3路信号那一路输出给A/D开关；如此处理可以降低处理电路成本。最后将信号进行A/D处理后可以通过计算机按照本公开提供的方法进行计算并输出局放点坐标。Wherein, the center frequency of the signal H is set at a frequency suitable for detecting the IJ intermediate joint PD signal, and the center frequency of the signal L is set at a frequency suitable for detecting the adjacent NJ intermediate joint PD signal, the signals H and L The center frequencies are different, and h, l are the signals to which the antenna is coupled. The amplified signal is modulated and transmitted to the monitoring station through the optical fiber, and the return signal is demodulated at the far end. The function of the noise gate in the figure is to compare the signal detected by the partial discharge detection structure with the noise signal coupled to the antenna, and treat the corresponding signals in the two as noise signals and reject them. The function of the continuous gate is to determine whether it is a partial discharge signal and output the signal according to the frequency of occurrence of the discharge pulse signal. The function of the NJ gate is to match the SL1 signal and the SL2 signal respectively outputted by the noise gates on both sides of IJ1 and IJ2, and to treat the signals corresponding to the SL1 signal and the SL2 signal as partial discharge pulses SL and output them. The function of the selection switch is to select the three signals IJ1, IJ2, and NJ to output to the A/D switch; this processing can reduce the processing circuit cost. Finally, after the signal is subjected to A/D processing, the computer can perform calculation according to the method provided by the present disclosure and output the coordinates of the PD.
信号H的中心频率设定在合适检测该IJ中间接头局放信号的频率上，较优的，H信号的中心频率范围可以设置为50MHZ---300MHz；信号L的中心频率设定在合适检测相邻的NJ中间接头局放信号的频率上,较优的，L的中心频率范围可以设置为1MHZ----50MHZ；信号H和L的中心频率各不相同，而h,l则为天线耦合到的信号，经过相应选频放大后的信号。The center frequency of the signal H is set at a frequency suitable for detecting the IJ intermediate joint PD signal. Preferably, the center frequency range of the H signal can be set to 50 MHz---300 MHz; the center frequency of the signal L is set to be suitable for detection. The frequency of the adjacent NJ intermediate connector PD signal is better, the center frequency range of L can be set to 1MHZ----50MHZ; the center frequencies of signals H and L are different, and h, l is the antenna. The coupled signal passes through the corresponding frequency-amplified signal.
在实际应用过程中，由于导电线缆的结构各不相同，局部放电检测结构检测的频率范围各有不同，H和L之间信号的中心频率范围相应进行变化后同样能够实现本公开的技术效果。In the actual application process, since the structure of the conductive cable is different, the frequency range of the partial discharge detecting structure is different, and the technical effect of the present disclosure can also be achieved after the central frequency range of the signal between H and L is changed accordingly. .
本发明实施例提供了一种高压电缆局部放电检测装置，包括：The embodiment of the invention provides a high voltage cable partial discharge detecting device, comprising:
获得模块，用于在电缆传输线路上获得两组局部放电信号，其中，在电缆传输线路上首尾两个接头附近设置电缆局部放电检测结构；Obtaining a module for obtaining two sets of partial discharge signals on a cable transmission line, wherein a cable partial discharge detecting structure is disposed near the first and last joints on the cable transmission line;
两个检测结构接收到的局部放电信号分别为：The partial discharge signals received by the two detection structures are:
X 1(t)＝S 1(t,r 1)+n 1(t)      (1) X 1 (t)=S 1 (t,r 1 )+n 1 (t) (1)
X 2(t)＝S 1(t,r 2)+n 2(t)     (2) X 2 (t)=S 1 (t,r 2 )+n 2 (t) (2)
其中，X 1(t)为t时刻第一个检测结构接收到的局部放电信号； Where X 1 (t) is the partial discharge signal received by the first detection structure at time t;
S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
X2(t)为t时刻第二个检测结构接收到的局部放电信号；X2(t) is the partial discharge signal received by the second detection structure at time t;
S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
第一确定模块，用于确定获得两组局部放电信号的最大相关延时时间τ m； a first determining module, configured to determine a maximum correlation delay time τ m of obtaining two sets of partial discharge signals;
对式(1)和(2)采用余弦信号进行分析，令信号方程为：The equations (1) and (2) are analyzed using a cosine signal, so that the signal equation is:
S1(t,r1)＝Ui e-ɑ r1cos w0(t-r1/v)     (3)S1(t,r1)=Ui e-ɑ r1cos w0(t-r1/v) (3)
S2(t,r2)＝Ui e-ɑ r2cos w0(t-r2/v)     (4)S2(t,r2)=Ui e-ɑ r2cos w0(t-r2/v) (4)
两个检测结构获得的局部放电信号的观测值的相关函数为：The correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
Figure PCTCN2018100091-appb-000046
Figure PCTCN2018100091-appb-000046
其中，X1(t)为t时刻第一个检测结构接收到的局部放电信号；Where X1(t) is the partial discharge signal received by the first detection structure at time t;
X2(t+τ)为t+τ时刻第二个检测结构接收到的局部放电信号；X2(t+τ) is the partial discharge signal received by the second detection structure at time t+τ;
V为局放信号在电缆中的传输速度；V is the transmission speed of the PD signal in the cable;
Figure PCTCN2018100091-appb-000047
为第一个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000047
The amplitude of the cosine signal received by the first detection mechanism;
Figure PCTCN2018100091-appb-000048
为第二个检测机构接收到的余弦信号的幅值；
Figure PCTCN2018100091-appb-000048
The amplitude of the cosine signal received by the second detection mechanism;
-a为衰减因子； -a is the attenuation factor;
T为信号周期；T is the signal period;
将式(1)和(2)代入式(5)可得：Substituting equations (1) and (2) into equation (5) yields:
Figure PCTCN2018100091-appb-000049
Figure PCTCN2018100091-appb-000049
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
假定局放信号和噪声是完全不相干的，(6)可以简化为：Assuming that the PD signal and noise are completely irrelevant, (6) can be simplified as:
Figure PCTCN2018100091-appb-000050
Figure PCTCN2018100091-appb-000050
其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
S2(t+τ，r2)为t+τ时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t+τ, r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号n 1(t)和n 2(t)完全不相干，那么将局放信号从噪声中分离出来，即： If the noise signals n 1 (t) and n 2 (t) are completely uncorrelated, then the PD signal is separated from the noise, ie:
Figure PCTCN2018100091-appb-000051
Figure PCTCN2018100091-appb-000051
其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
S 2(t+τ，r 2)为t+τ时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t + τ, r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 τ from the partial discharge distance r 2 ;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
T为信号周期；T is the signal period;
如果噪声信号与局部放电信号相干，则对局部放电信号进行去噪处理，压制噪声n 1(t)和n 2(t)的干扰，得到(8)式； If the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
对式(8)在一个周期进行积分；已知局放信号的周期为
Figure PCTCN2018100091-appb-000052
那么将式(3)和(4)代入式(8)，经过积分可得： Integrate equation (8) in one cycle; the period of known partial discharge signal is
Figure PCTCN2018100091-appb-000052
Then substituting equations (3) and (4) into equation (8), after integration, you can get:
Figure PCTCN2018100091-appb-000053
Figure PCTCN2018100091-appb-000053
其中：
Figure PCTCN2018100091-appb-000054
among them:
Figure PCTCN2018100091-appb-000054
由(9)可知，S 1和S 2两个局放信号的相关函数是由一个特殊函数
Figure PCTCN2018100091-appb-000055
(辛格函数)与一个常数因子k 0的乘积构成；辛格函数的极大值为： It can be seen from (9) that the correlation function of the two PD signals of S 1 and S 2 is a special function.
Figure PCTCN2018100091-appb-000055
(Singer function) is composed of a product of a constant factor k 0 ; the maximum value of the singular function is:
Figure PCTCN2018100091-appb-000056
Figure PCTCN2018100091-appb-000056
所以相关函数的最大值对应着：So the maximum value of the correlation function corresponds to:
Figure PCTCN2018100091-appb-000057
其值趋于0      (11)
Figure PCTCN2018100091-appb-000057
Its value tends to 0 (11)
w0不可能为0，所以：
Figure PCTCN2018100091-appb-000058
W0 cannot be 0, so:
Figure PCTCN2018100091-appb-000058
Figure PCTCN2018100091-appb-000059
Figure PCTCN2018100091-appb-000059
其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
第二确定模块，确定局部放电点的位置，其中，根据式(13)可得：a second determining module determines a position of the partial discharge point, wherein, according to formula (13),
r 1＝r 2-vτ m     (14) r 1 =r 2 -vτ m (14)
其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
设第一检测结构和第二检测结构的距离为D,且r 1＝L,则r 2＝D-L,可得： Let the distance between the first detection structure and the second detection structure be D, and r 1 = L, then r 2 = DL, which can be obtained:
L＝D-L-vτ m    (15) L=DL-vτ m (15)
则局放点与第一检测结构的水平距离L为：Then the horizontal distance L between the local discharge point and the first detection structure is:
Figure PCTCN2018100091-appb-000060
Figure PCTCN2018100091-appb-000060
在一些实施例中，所述电缆局部放电检测结构，包括第一电缆和第二电缆；所述第一电缆和第二电缆通过接头连接；所述第一电缆靠近所述接头处外屏层的外表面设置有第一金属箔；所述第二电缆靠近所述接头处外屏层的外表面设置有第二金属箔；所述第一金属箔和第二金属箔之间电连接有检测阻抗；In some embodiments, the cable partial discharge detecting structure includes a first cable and a second cable; the first cable and the second cable are connected by a joint; the first cable is adjacent to an outer layer of the joint The outer surface is provided with a first metal foil; the second cable is provided with a second metal foil near the outer surface of the outer layer; the first metal foil and the second metal foil are electrically connected with a detection impedance ;
所述接头内设置有绝缘筒；所述第一电缆和第二电缆的金属屏蔽层通过所述绝缘筒断开。An insulating cylinder is disposed in the joint; the metal shield of the first cable and the second cable is disconnected through the insulating cylinder.
两个所述检测结构的接头之间串联有中间接头；所述中间接头两侧电缆的金属屏蔽层连接为一体结构。An intermediate joint is connected in series between the joints of the two detecting structures; the metal shielding layers of the cables on both sides of the intermediate joint are connected as a unitary structure.
所述装置还包括：The device also includes:
去噪模块，用于采用下述步骤去除局部放电信号的噪声：The denoising module is used to remove the noise of the partial discharge signal by the following steps:
在所述首尾两个接头处的电缆局部放电检测结构处分别设置第一天线、第二天线；Providing a first antenna and a second antenna respectively at the cable partial discharge detecting structure at the first and last joints;
将首接头处的局部放电检测信号和第一天线耦合信号进行选频放大，将尾接头处的局部放电检测信号和第二天线耦合信号进行选频放大；Selecting and amplifying the partial discharge detection signal and the first antenna coupling signal at the first joint, and selecting and amplifying the partial discharge detection signal and the second antenna coupling signal at the tail joint;
将选频放大后的局部放电检测信号与天线耦合信号中对应的信号视为噪声信号并丢弃；Treating the selected partial discharge detection signal and the corresponding signal in the antenna coupling signal as noise signals and discarding;
将首接头处接收到的相邻的中间接头局部放电信号与尾接头处接收到的相邻的中间接头局部放电信号中相对应的信号输出；并将首接头处接收到的该接头局部放电信号直接输出；将尾接头处接收到的该接头局部信号直接输出；And outputting a signal corresponding to the adjacent intermediate joint partial discharge signal received at the first joint and the adjacent intermediate joint partial discharge signal received at the tail joint; and receiving the joint partial discharge signal at the first joint Direct output; direct output of the joint local signal received at the tail joint;
将输出的信号根据放电脉冲信号出现的频繁程度判断是否为局部放电信号并输出。The output signal is judged based on the frequency of occurrence of the discharge pulse signal as a partial discharge signal and output.
在一些实施例中，所述第二确定模块，具体用于确定合适检测首接头局放信号的频率范围；确定合适检测尾接头局放信号的频率范围；确定合适检测中间接头局放信号的频率范围；首接头处按照首接头局放信号检测范围和相邻的中间接头局放信号的频率范围进行选频；尾接头处按照尾接头局放信号检测范围和相邻的中间接头局放信号的频率范围进行选频。In some embodiments, the second determining module is specifically configured to determine a frequency range suitable for detecting a PD signal of the first connector; determine a frequency range suitable for detecting a PD signal of the tail connector; and determine a frequency of detecting a PD signal of the intermediate connector. Range; the first joint is selected according to the detection range of the first joint PD signal and the frequency range of the adjacent intermediate joint PD signal; the tail joint is in accordance with the tail joint PD signal detection range and the adjacent intermediate joint PD signal The frequency range is selected.
一种计算机存储介质，所述计算机存储介质存储有计算机可执行指令；所述计算机可执行指令被执行后，能够实现前述的高压电缆局部放电检测方法中的一个或多个。该计算机存储介质可包括：非瞬间存储介质。A computer storage medium storing computer executable instructions; the computer executable instructions being executable to implement one or more of the aforementioned high voltage cable partial discharge detection methods. The computer storage medium can include: a non-transitory storage medium.
其中，持续门、NJ门、噪声门电路都可以通过较为常规的电路来实现。Among them, the continuous gate, NJ gate, and noise gate circuit can be realized by a relatively conventional circuit.
以上详细描述了本公开的较佳具体实施例。应当理解，本领域的普通 技术人员无需创造性劳动就可以根据本公开的构思作出诸多修改和变化。因此，凡本技术领域中技术人员依本公开的构思在现有技术的基础上通过逻辑分析、推理或者有限的实验可以得到的技术方案，皆应在由权利要求书所确定的保护范围内。The above has described in detail the preferred embodiments of the present disclosure. It will be appreciated that many modifications and variations can be made by those skilled in the art without departing from the scope of the invention. Therefore, any technical solution that can be obtained by a person skilled in the art based on the prior art based on the prior art by logic analysis, reasoning or limited experimentation should be within the scope of protection determined by the claims.

Claims (11)

  1. 一种高压电缆局部放电检测方法，包括以下步骤：A method for detecting partial discharge of a high voltage cable, comprising the following steps:
    1)在电缆传输线路上获得两组局部放电信号，其中，在电缆传输线路上首尾两个接头处设置电缆局部放电检测结构；两个检测结构接收到的局部放电信号分别为：1) Two sets of partial discharge signals are obtained on the cable transmission line, wherein the cable partial discharge detection structure is arranged at the first and last joints on the cable transmission line; the partial discharge signals received by the two detection structures are:
    X 1(t)＝S 1(t,r 1)+n 1(t)           (1) X 1 (t)=S 1 (t,r 1 )+n 1 (t) (1)
    X 2(t)＝S 1(t,r 2)+n 2(t)           (2) X 2 (t)=S 1 (t,r 2 )+n 2 (t) (2)
    其中，X 1(t)为t时刻第一个检测结构接收到的局部放电信号； Where X 1 (t) is the partial discharge signal received by the first detection structure at time t;
    S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
    n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
    r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
    X2(t)为t时刻第二个检测结构接收到的局部放电信号；X2(t) is the partial discharge signal received by the second detection structure at time t;
    S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
    n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
    r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
    2)确定获得两组局部放电信号的最大相关延时时间τm；2) determining the maximum correlation delay time τm of the two sets of partial discharge signals;
    对式(1)和(2)采用余弦信号进行分析，令信号方程为：The equations (1) and (2) are analyzed using a cosine signal, so that the signal equation is:
    S1(t,r1)＝Ui e-ɑ r1cos w0(t-r1/v)       (3)S1(t,r1)=Ui e-ɑ r1cos w0(t-r1/v) (3)
    S2(t,r2)＝Ui e-ɑ r2cos w0(t-r2/v)       (4)S2(t,r2)=Ui e-ɑ r2cos w0(t-r2/v) (4)
    两个检测结构获得的局部放电信号的观测值的相关函数为：The correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
    Figure PCTCN2018100091-appb-100001
    Figure PCTCN2018100091-appb-100001
    其中，X1(t)为t时刻第一个检测结构接收到的局部放电信号；Where X1(t) is the partial discharge signal received by the first detection structure at time t;
    X2(t+τ)为t+τ时刻第二个检测结构接收到的局部放电信号；X2(t+τ) is the partial discharge signal received by the second detection structure at time t+τ;
    V为局放信号在电缆中的传输速度；V is the transmission speed of the PD signal in the cable;
    Figure PCTCN2018100091-appb-100002
    为第一个检测机构接收到的余弦信号的幅值；
    Figure PCTCN2018100091-appb-100002
    The amplitude of the cosine signal received by the first detection mechanism;
    Figure PCTCN2018100091-appb-100003
    为第二个检测机构接收到的余弦信号的幅值；
    Figure PCTCN2018100091-appb-100003
    The amplitude of the cosine signal received by the second detection mechanism;
    -a为衰减因子；-a is the attenuation factor;
    T为信号周期；T is the signal period;
    将式(1)和(2)代入式(5)可得：Substituting equations (1) and (2) into equation (5) yields:
    Figure PCTCN2018100091-appb-100004
    Figure PCTCN2018100091-appb-100004
    其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
    n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
    r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
    S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
    n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
    r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
    T为信号周期；T is the signal period;
    假定局放信号和噪声是完全不相干的，(6)可以简化为：Assuming that the PD signal and noise are completely irrelevant, (6) can be simplified as:
    Figure PCTCN2018100091-appb-100005
    Figure PCTCN2018100091-appb-100005
    其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
    n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
    r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
    S2(t+τ，r2)为t+τ时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t+τ, r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
    n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
    r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
    T为信号周期；T is the signal period;
    如果噪声信号n 1(t)和n 2(t)完全不相干，那么将局放信号从噪声中分离出来，即： If the noise signals n 1 (t) and n 2 (t) are completely uncorrelated, then the PD signal is separated from the noise, ie:
    Figure PCTCN2018100091-appb-100006
    Figure PCTCN2018100091-appb-100006
    其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
    r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
    S 2(t+τ，r 2)为t+τ时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t + τ, r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 τ from the partial discharge distance r 2 ;
    r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
    T为信号周期；T is the signal period;
    如果噪声信号与局部放电信号相干，则对局部放电信号进行去噪处理，压制噪声n 1(t)和n 2(t)的干扰，得到(8)式； If the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
    对式(8)在一个周期进行积分；已知局放信号的周期为
    Figure PCTCN2018100091-appb-100007
    那么 将式(3)和(4)代入式(8)，经过积分可得：     Integrate equation (8) in one cycle; the period of known partial discharge signal is
    Figure PCTCN2018100091-appb-100007
    Then substituting equations (3) and (4) into equation (8), after integration, you can get:
    Figure PCTCN2018100091-appb-100008
    Figure PCTCN2018100091-appb-100008
    其中：
    Figure PCTCN2018100091-appb-100009
    among them:
    Figure PCTCN2018100091-appb-100009
    由(9)可知，S 1和S 2两个局放信号的相关函数是由一个特殊函数
    Figure PCTCN2018100091-appb-100010
    (辛格函数)与一个常数因子k 0的乘积构成；辛格函数的极大值为：     It can be seen from (9) that the correlation function of the two PD signals of S 1 and S 2 is a special function.
    Figure PCTCN2018100091-appb-100010
    (Singer function) is composed of a product of a constant factor k 0 ; the maximum value of the singular function is:
    Figure PCTCN2018100091-appb-100011
    Figure PCTCN2018100091-appb-100011
    所以相关函数的最大值对应着：So the maximum value of the correlation function corresponds to:
    Figure PCTCN2018100091-appb-100012
    其值趋于0         (11)
    Figure PCTCN2018100091-appb-100012
    Its value tends to 0 (11)
    w0不可能为0，所以：
    Figure PCTCN2018100091-appb-100013
    W0 cannot be 0, so:
    Figure PCTCN2018100091-appb-100013
    Figure PCTCN2018100091-appb-100014
    Figure PCTCN2018100091-appb-100014
    其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
    r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
    v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
    τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
    3)确定局部放电点的位置，其中，根据式(13)可得：3) Determine the position of the partial discharge point, wherein, according to formula (13):
    r 1＝r 2-vτ m         (14) r 1 =r 2 -vτ m (14)
    其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
    r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
    v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
    τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
    设第一检测结构和第二检测结构的距离为D,且r 1＝L,则r 2＝D-L,可得： Let the distance between the first detection structure and the second detection structure be D, and r 1 = L, then r 2 = DL, which can be obtained:
    L＝D-L-vτ m      (15) L=DL-vτ m (15)
    则局放点与第一检测结构的水平距离L为：Then the horizontal distance L between the local discharge point and the first detection structure is:
    Figure PCTCN2018100091-appb-100015
    Figure PCTCN2018100091-appb-100015
  2. 如权利要求1所述的高压电缆局部放电检测方法，其中，所述步骤1)中，所述电缆局部放电检测结构，包括第一电缆和第二电缆；所述第一电缆和第二电缆通过接头连接；所述第一电缆靠近所述接头处外屏层的外表面设置有第一金属箔；所述第二电缆靠近所述接头处外屏层的外表面设置有第二金属箔；所述第一金属箔和第二金属箔之间电连接有检测阻抗；The high-voltage cable partial discharge detecting method according to claim 1, wherein in the step 1), the cable partial discharge detecting structure includes a first cable and a second cable; and the first cable and the second cable pass a first metal foil is disposed on an outer surface of the outer layer of the first cable near the joint; a second metal foil is disposed on an outer surface of the outer layer of the second cable near the joint; The first metal foil and the second metal foil are electrically connected to each other with a detection impedance;
    所述接头内设置有绝缘筒；所述第一电缆和第二电缆的金属屏蔽层通过所述绝缘筒断开。An insulating cylinder is disposed in the joint; the metal shield of the first cable and the second cable is disconnected through the insulating cylinder.
  3. 如权利要求1所述的高压电缆局部放电检测方法，其中，所述电缆传输线路上有中间接头；所述中间接头两侧电缆的金属屏蔽层连接为一体结构。The high-voltage cable partial discharge detecting method according to claim 1, wherein the cable transmission line has an intermediate joint; and the metal shield layers of the cables on both sides of the intermediate joint are connected as a unitary structure.
  4. 如权利要求1至3任一项所述的高压电缆局部放电检测方法，其中，所述方法还包括：采用下述步骤去除局部放电信号的噪声：The high voltage cable partial discharge detecting method according to any one of claims 1 to 3, wherein the method further comprises: removing noise of the partial discharge signal by the following steps:
    11)在所述首尾两个接头处的电缆局部放电检测结构处分别设置第一天线、第二天线；11) respectively providing a first antenna and a second antenna at the cable partial discharge detecting structure at the first and last joints;
    12)将首接头处的局部放电检测信号和第一天线耦合信号进行选频放大，将尾接头处的局部放电检测信号和第二天线耦合信号进行选频放大；12) performing frequency selective amplification on the partial discharge detection signal and the first antenna coupling signal at the first joint, and frequency selective amplification of the partial discharge detection signal and the second antenna coupling signal at the tail joint;
    13)将选频放大后的局部放电检测信号与天线耦合信号中对应的信号视为噪声信号并丢弃；13) treating the partial discharge detection signal after the frequency selective amplification and the corresponding signal in the antenna coupling signal as a noise signal and discarding;
    14)将首接头处接收到的相邻的中间接头局部放电信号与尾接头处接收到的相邻的中间接头局部放电信号中相对应的信号输出；并将首接头处接收到的该接头局部放电信号直接输出；将尾接头处接收到的该接头局部信号直接输出；14) outputting a signal corresponding to a partial discharge signal of the adjacent intermediate joint received at the first joint and a partial discharge signal of the adjacent intermediate joint received at the tail joint; and receiving the joint at the joint The discharge signal is directly output; the local signal of the joint received at the tail joint is directly output;
    15)将步骤14)中输出的信号根据放电脉冲信号出现的频繁程度判断是否为局部放电信号并输出。15) The signal outputted in the step 14) is judged based on the frequency of occurrence of the discharge pulse signal as a partial discharge signal and output.
  5. 如权利要求4所述的高压电缆局部放电检测方法，其中，所述步骤13)中，按照以下步骤进行信号的选频放大：The high-voltage cable partial discharge detecting method according to claim 4, wherein in the step 13), the frequency selective amplification of the signal is performed according to the following steps:
    131)确定合适检测首接头局放信号的频率范围；131) determining a frequency range suitable for detecting a PD signal of the first joint;
    132)确定合适检测尾接头局放信号的频率范围；132) determining a frequency range suitable for detecting a PD signal of the tail joint;
    133)确定合适检测中间接头局放信号的频率范围；133) determining a frequency range suitable for detecting an intermediate joint PD signal;
    134)首接头处按照首接头局放信号检测范围和相邻的中间接头局放信号的频率范围进行选频；134) The first joint is selected according to the detection range of the first joint PD signal and the frequency range of the adjacent intermediate joint PD signal;
    尾接头处按照尾接头局放信号检测范围和相邻的中间接头局放信号的频率范围进行选频。The tail joint is selected according to the detection range of the tail joint PD signal and the frequency range of the adjacent intermediate joint PD signal.
  6. 一种高压电缆局部放电检测装置，包括：A high voltage cable partial discharge detecting device comprises:
    获得模块，用于在电缆传输线路上获得两组局部放电信号，其中，在电缆传输线路上首尾两个接头附近设置电缆局部放电检测结构；Obtaining a module for obtaining two sets of partial discharge signals on a cable transmission line, wherein a cable partial discharge detecting structure is disposed near the first and last joints on the cable transmission line;
    两个检测结构接收到的局部放电信号分别为：The partial discharge signals received by the two detection structures are:
    X 1(t)＝S 1(t,r 1)+n 1(t)       (1) X 1 (t)=S 1 (t,r 1 )+n 1 (t) (1)
    X 2(t)＝S 1(t,r 2)+n 2(t)       (2) X 2 (t)=S 1 (t,r 2 )+n 2 (t) (2)
    其中，X 1(t)为t时刻第一个检测结构接收到的局部放电信号； Where X 1 (t) is the partial discharge signal received by the first detection structure at time t;
    S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； S 1 (t, r 1 ) is the observed value of the signal obtained by the first detection structure at a distance t from the partial discharge distance r 1 ;
    n 1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声； n 1 (t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
    r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
    X2(t)为t时刻第二个检测结构接收到的局部放电信号；X2(t) is the partial discharge signal received by the second detection structure at time t;
    S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获 得的信号观测值；S2(t, r2) is the signal observation obtained by the second detection structure at a distance t from the partial discharge distance r2;
    n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
    r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
    第一确定模块，用于确定获得两组局部放电信号的最大相关延时时间τm；a first determining module, configured to determine a maximum correlation delay time τm of obtaining two sets of partial discharge signals;
    对式(1)和(2)采用余弦信号进行分析，令信号方程为：The equations (1) and (2) are analyzed using a cosine signal, so that the signal equation is:
    S1(t,r1)＝Ui e-ɑ r1cos w0(t-r1/v)       (3)S1(t,r1)=Ui e-ɑ r1cos w0(t-r1/v) (3)
    S2(t,r2)＝Ui e-ɑ r2cos w0(t-r2/v)       (4)S2(t,r2)=Ui e-ɑ r2cos w0(t-r2/v) (4)
    两个检测结构获得的局部放电信号的观测值的相关函数为：The correlation function of the observed values of the partial discharge signals obtained by the two detection structures is:
    Figure PCTCN2018100091-appb-100016
    Figure PCTCN2018100091-appb-100016
    其中，X1(t)为t时刻第一个检测结构接收到的局部放电信号；Where X1(t) is the partial discharge signal received by the first detection structure at time t;
    X2(t+τ)为t+τ时刻第二个检测结构接收到的局部放电信号；X2(t+τ) is the partial discharge signal received by the second detection structure at time t+τ;
    V为局放信号在电缆中的传输速度；V is the transmission speed of the PD signal in the cable;
    Figure PCTCN2018100091-appb-100017
    为第一个检测机构接收到的余弦信号的幅值；
    Figure PCTCN2018100091-appb-100017
    The amplitude of the cosine signal received by the first detection mechanism;
    Figure PCTCN2018100091-appb-100018
    为第二个检测机构接收到的余弦信号的幅值；
    Figure PCTCN2018100091-appb-100018
    The amplitude of the cosine signal received by the second detection mechanism;
    -a为衰减因子；-a is the attenuation factor;
    T为信号周期；T is the signal period;
    将式(1)和(2)代入式(5)可得：Substituting equations (1) and (2) into equation (5) yields:
    Figure PCTCN2018100091-appb-100019
    Figure PCTCN2018100091-appb-100019
    其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
    n1(t)为第一个检测结构获得的信号观测值传输过程中的随机 噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
    r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
    S2(t,r2)为t时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t, r2) is the signal observation value obtained by the second detection structure at the time t from the partial discharge distance r2;
    n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
    r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
    T为信号周期；T is the signal period;
    假定局放信号和噪声是完全不相干的，(6)可以简化为：Assuming that the PD signal and noise are completely irrelevant, (6) can be simplified as:
    Figure PCTCN2018100091-appb-100020
    Figure PCTCN2018100091-appb-100020
    其中，S1(t,r1)为t时刻，距离局部放电距离r1处第一个检测结构获得的信号观测值；Wherein, S1(t, r1) is a signal observation value obtained by the first detection structure at a distance t from the partial discharge distance r1;
    n1(t)为第一个检测结构获得的信号观测值传输过程中的随机噪声；N1(t) is the random noise during the transmission of the signal observation obtained by the first detection structure;
    r1为第一个检测结构距离局部放电点的距离；R1 is the distance of the first detection structure from the partial discharge point;
    S2(t+τ，r2)为t+τ时刻，距离局部放电距离r2处第二个检测结构获得的信号观测值；S2(t+τ, r2) is the signal observation obtained by the second detection structure at a distance t2 from the partial discharge distance r2;
    n2(t)为第二个检测结构获得的信号观测值传输过程中的随机噪声；N2(t) is the random noise during the transmission of the signal observation obtained by the second detection structure;
    r2为第二个检测结构距离局部放电点的距离；R2 is the distance of the second detection structure from the partial discharge point;
    T为信号周期；T is the signal period;
    如果噪声信号n 1(t)和n 2(t)完全不相干，那么将局放信号从噪声中分离出来，即： If the noise signals n 1 (t) and n 2 (t) are completely uncorrelated, then the PD signal is separated from the noise, ie:
    Figure PCTCN2018100091-appb-100021
    Figure PCTCN2018100091-appb-100021
    其中，S 1(t,r 1)为t时刻，距离局部放电距离r 1处第一个检测结构获得的信号观测值； Wherein, S 1 (t, r 1 ) is a signal observation value obtained by the first detection structure at a time t from the partial discharge distance r 1 ;
    r 1为第一个检测结构距离局部放电点的距离； r 1 is the distance of the first detection structure from the partial discharge point;
    S 2(t+τ，r 2)为t+τ时刻，距离局部放电距离r 2处第二个检测结构获得的信号观测值； S 2 (t + τ, r 2 ) is the signal observation obtained by the second detection structure at a distance t 2 τ from the partial discharge distance r 2 ;
    r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
    T为信号周期；T is the signal period;
    如果噪声信号与局部放电信号相干，则对局部放电信号进行去噪处理，压制噪声n 1(t)和n 2(t)的干扰，得到(8)式； If the noise signal is coherent with the partial discharge signal, the partial discharge signal is denoised, and the interference of noises n 1 (t) and n 2 (t) is suppressed to obtain (8);
    对式(8)在一个周期进行积分；已知局放信号的周期为
    Figure PCTCN2018100091-appb-100022
    那么将式(3)和(4)代入式(8)，经过积分可得：     Integrate equation (8) in one cycle; the period of known partial discharge signal is
    Figure PCTCN2018100091-appb-100022
    Then substituting equations (3) and (4) into equation (8), after integration, you can get:
    Figure PCTCN2018100091-appb-100023
    Figure PCTCN2018100091-appb-100023
    其中：
    Figure PCTCN2018100091-appb-100024
    among them:
    Figure PCTCN2018100091-appb-100024
    由(9)可知，S 1和S 2两个局放信号的相关函数是由一个特殊函数
    Figure PCTCN2018100091-appb-100025
    (辛格函数)与一个常数因子k 0的乘积构成；辛格函数的极大值为：     It can be seen from (9) that the correlation function of the two PD signals of S 1 and S 2 is a special function.
    Figure PCTCN2018100091-appb-100025
    (Singer function) is composed of a product of a constant factor k 0 ; the maximum value of the singular function is:
    Figure PCTCN2018100091-appb-100026
    Figure PCTCN2018100091-appb-100026
    所以相关函数的最大值对应着：So the maximum value of the correlation function corresponds to:
    Figure PCTCN2018100091-appb-100027
    其值趋于0       (11)
    Figure PCTCN2018100091-appb-100027
    Its value tends to 0 (11)
    w0不可能为0，所以：
    Figure PCTCN2018100091-appb-100028
    W0 cannot be 0, so:
    Figure PCTCN2018100091-appb-100028
    Figure PCTCN2018100091-appb-100029
    Figure PCTCN2018100091-appb-100029
    其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
    r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
    v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
    τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
    第二确定模块，确定局部放电点的位置，其中，根据式(13)可得：a second determining module determines a position of the partial discharge point, wherein, according to formula (13),
    r 1＝r 2-vτ m        (14) r 1 =r 2 -vτ m (14)
    其中，r 1为第一个检测结构距离局部放电点的距离； Where r 1 is the distance of the first detection structure from the partial discharge point;
    r 2为第二个检测结构距离局部放电点的距离； r 2 is the distance of the second detection structure from the partial discharge point;
    v为局部放电信号在电缆中的传输速度；v is the transmission speed of the partial discharge signal in the cable;
    τ m为两组局部放电信号的最大相关延时时间； τ m is the maximum correlation delay time of the two groups of partial discharge signals;
    设第一检测结构和第二检测结构的距离为D,且r 1＝L,则r 2＝D-L,可得： Let the distance between the first detection structure and the second detection structure be D, and r 1 = L, then r 2 = DL, which can be obtained:
    L＝D-L-vτ m       (15) L=DL-vτ m (15)
    则局放点与第一检测结构的水平距离L为：Then the horizontal distance L between the local discharge point and the first detection structure is:
    Figure PCTCN2018100091-appb-100030
    Figure PCTCN2018100091-appb-100030
  7. 如权利要求6所述的高压电缆局部放电检测装置，其中，所述电缆局部放电检测结构，包括第一电缆和第二电缆；所述第一电缆和第二电缆通过接头连接；所述第一电缆靠近所述接头处外屏层的外表面设置有第一金属箔；所述第二电缆靠近所述接头处外屏层的外表面设置有第二金属箔；所述第一金属箔和第二金属箔之间电连接有检测阻抗；The high-voltage cable partial discharge detecting device according to claim 6, wherein said cable partial discharge detecting structure comprises a first cable and a second cable; said first cable and said second cable are connected by a joint; said first a first metal foil is disposed on an outer surface of the outer layer of the cable near the joint; a second metal foil is disposed on an outer surface of the outer layer adjacent to the joint; the first metal foil and the first metal foil The electrical connection between the two metal foils has a detection impedance;
    所述接头内设置有绝缘筒；所述第一电缆和第二电缆的金属屏蔽层通过所述绝缘筒断开。An insulating cylinder is disposed in the joint; the metal shield of the first cable and the second cable is disconnected through the insulating cylinder.
  8. 如权利要求6所述的高压电缆局部放电检测装置，其中，所述电缆传输线路上有中间接头；所述中间接头两侧电缆的金属屏蔽层连接为一体结构。The high-voltage cable partial discharge detecting device according to claim 6, wherein said cable transmission line has an intermediate joint; and said metal shield layers of said two sides of said intermediate joint are connected in a unitary structure.
  9. 如权利要求6至8任一项所述的高压电缆局部放电检测装置，其中，The high-voltage cable partial discharge detecting device according to any one of claims 6 to 8, wherein
    去噪模块，用于采用下述步骤去除局部放电信号的噪声：The denoising module is used to remove the noise of the partial discharge signal by the following steps:
    在所述首尾两个接头处的电缆局部放电检测结构处分别设置第一天线、第二天线；Providing a first antenna and a second antenna respectively at the cable partial discharge detecting structure at the first and last joints;
    将首接头处的局部放电检测信号和第一天线耦合信号进行选频放大，将尾接头处的局部放电检测信号和第二天线耦合信号进行选频放大；Selecting and amplifying the partial discharge detection signal and the first antenna coupling signal at the first joint, and selecting and amplifying the partial discharge detection signal and the second antenna coupling signal at the tail joint;
    将选频放大后的局部放电检测信号与天线耦合信号中对应的信号视为噪声信号并丢弃；Treating the selected partial discharge detection signal and the corresponding signal in the antenna coupling signal as noise signals and discarding;
    将首接头处接收到的相邻的中间接头局部放电信号与尾接头处接收到的相邻的中间接头局部放电信号中相对应的信号输出；并将首接头处接收到的该接头局部放电信号直接输出；将尾接头处接收到的该接头局部信号直接输出；And outputting a signal corresponding to the adjacent intermediate joint partial discharge signal received at the first joint and the adjacent intermediate joint partial discharge signal received at the tail joint; and receiving the joint partial discharge signal at the first joint Direct output; direct output of the joint local signal received at the tail joint;
    将输出的信号根据放电脉冲信号出现的频繁程度判断是否为局部放电信号并输出。The output signal is judged based on the frequency of occurrence of the discharge pulse signal as a partial discharge signal and output.
  10. 如权利要求9所述的高压电缆局部放电检测装置，其中，所述第二确定模块，具体用于确定合适检测首接头局放信号的频率范围；确定合适检测尾接头局放信号的频率范围；确定合适检测中间接头局放信号的频率范围；首接头处按照首接头局放信号检测范围和相邻的中间接头局放信号的频率范围进行选频；尾接头处按照尾接头局放信号检测范围和相邻的中间接头局放信号的频率范围进行选频。The high-voltage cable partial discharge detecting device according to claim 9, wherein the second determining module is specifically configured to determine a frequency range suitable for detecting a partial joint partial discharge signal; and determining a frequency range suitable for detecting a tail joint partial discharge signal; Determine the frequency range suitable for detecting the signal of the intermediate joint PD; the first joint is selected according to the detection range of the first joint PD signal and the frequency range of the adjacent intermediate joint PD signal; the tail joint is according to the tail joint PD signal detection range. The frequency range of the adjacent intermediate connector PD signal is selected.
  11. 一种计算机存储介质，所述计算机存储介质存储有计算机可执行指令；所述计算机可执行指令被执行后，能够实现权利要求1至5任一项提供的方法。A computer storage medium storing computer executable instructions; the computer executable instructions being executable to implement the method of any one of claims 1 to 5.
PCT/CN2018/100091 2018-01-30 2018-08-10 Method and apparatus for partial discharge detection of high-voltage cable WO2019148794A1 (en)

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