CN216847995U - Sheath circulation on-line monitoring device with fault recording function - Google Patents

Abstract

The utility model relates to a cable circulation monitoring technology field discloses a sheath circulation on-line monitoring device of area trouble record ripples, include the signal acquisition module, analog signal conditioning module, AD sampling module, control module and the communication module that connect gradually along the current transmission direction, wherein, the signal acquisition module is including the load current sensor who is used for gathering cable current load and the three-phase circulation sensor who gathers the cable circulation, control module is used for calculating the three-phase circulation value that three-phase circulation sensor gathered with the load current value's that load current sensor gathered ratio, when taking place ground fault, control module will take notes the circulation waveform data of preceding a plurality of ms, back a plurality of ms of trouble emergence. The utility model discloses thereby carry out the comparison with the three-phase circulation current value of cable and load current value and synthesize the judgement to the cable circulation, avoided partial misstatement.

Description

Sheath circulation on-line monitoring device with fault recording function

Technical Field

The utility model relates to a cable circulation monitoring technology field, concretely relates to sheath circulation on-line monitoring device of band failure record ripples.

Background

Along with the acceleration of urbanization process, urban electric power facility is the miniaturization development of net gradually, and the overhead cable uses in urban power transmission and reduces gradually, and XLPE high tension cable uses gradually, and the cable insulation problem is prominent day by day, shows gradually the importance to the monitoring of cable equipment body.

When the cable is in an operating state, induced electromotive force is generated on a metal sheath of the cable, so that sheath current, namely circulating current is generated, in order to reduce the sheath current generated by induction, a cable grounding system needs to be reliably designed, and a grounding protection device generally adopts three-phase cross interconnection grounding or terminal for protection grounding.

The traditional cable circulation monitoring device only judges the circulation size: the cable is judged to have the ground fault by setting a circulating current alarm threshold and monitoring the circulating current sudden change, the threshold is mainly set by experience, but the circulating current of the cable is increased along with the increase of load current, particularly in summer, the cable is always operated at full load, the corresponding circulating current is also increased, and therefore the situations of false alarm and the like are easily caused.

SUMMERY OF THE UTILITY MODEL

The utility model provides a take sheath circulation on-line monitoring device of trouble record ripples can reduce the condition of wrong report.

The utility model discloses a following technical scheme realizes:

a sheath circulation on-line monitoring device with fault recording comprises a signal acquisition module, an analog signal conditioning module, an AD sampling module, a storage module, a control module and a communication module which are sequentially connected along a current transmission direction, wherein the signal acquisition module comprises a load current sensor for acquiring a cable current load and a three-phase circulation sensor for acquiring a cable circulation, the analog signal conditioning module is used for conditioning and filtering acquired electric signals, the AD sampling module is used for AD converting the electric signals conditioned by the analog signal conditioning module and transmitting the electric signals to the control module, the communication module is used for carrying out time synchronization with a network, the control module is used for calculating the ratio of a three-phase circulation value acquired by the three-phase circulation sensor to a load current value acquired by the load current sensor, when a ground fault occurs, the control module records circulation waveform data of a plurality of ms before and a plurality of ms after the fault, and transmits the circulation waveform data to the storage module.

Preferably, the communication module comprises an Ethernet chip U31 and peripheral circuits of the Ethernet chip.

And as optimization, the storage module is a CPU memory and is connected with the control module and used for storing circulating current wave recording data.

As optimization, the protection device further comprises an IO module, the IO module is connected with the control module, and the control module transmits a protection signal corresponding to the ground fault to the external cable protection device through the IO module.

Preferably, the IO module includes a plurality of relays connected to an external cable protection device.

As an optimization, the signal acquisition module further comprises a temperature sensor for acquiring the temperature of the cable joint.

Preferably, the signal acquisition module further comprises a total grounding sensor, and the total grounding sensor is used for acquiring the grounding current value of the cable sheath.

Preferably, the AD sampling module comprises a sampling chip U34 and a sampling peripheral circuit.

As an optimization, the control module comprises a fourier transform module, a calibration module, a calculation module, a comparison module and a fault recording module which are sequentially connected along a current transmission direction, an input end of the fourier transform module is connected with the AD sampling module, the fault recording module is respectively connected with the storage module and the communication module, the fourier transform module is used for performing fourier transform on a three-phase circulating current value transmitted by the AD sampling module to obtain an amplitude and a phase of a power frequency partial signal of the three-phase circulating current value, the calibration module is used for calibrating the three-phase circulating current value to obtain a three-phase phasor of the three-phase circulating current value, the calculation module is used for calculating the effective three-phase phasor to obtain a zero-sequence phasor, the comparison module is used for comparing the three-phase phasor with the load current value to obtain a ratio, and the fault recording module is used for judging whether to perform fault recording according to the ratio, and executing fault wave recording or fault-free wave recording according to the judgment result.

And optimally, the circulation waveform data are a three-phase circulation value and a load current value of the cable.

Compared with the prior art, the utility model, following advantage and beneficial effect have:

the utility model discloses thereby carry out the comparison with the three-phase circulation current value of cable and load current value and synthesize the judgement to the cable circulation, avoided the part wrong report.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principles of the invention. In the drawings:

fig. 1 is a connection diagram of a frame structure of a sheath circulating current on-line monitoring device with fault recording according to the present invention;

FIG. 2 is a circuit diagram of the AD sampling module of FIG. 1;

FIG. 3 is a circuit diagram of the analog signal conditioning module of FIG. 1;

fig. 4 is a circuit diagram of the communication module of fig. 1.

Reference numbers and corresponding part names in the drawings:

100-a signal acquisition module, 110-a load current sensor, 120-a three-phase circulating current sensor, 130-a temperature sensor, 140-a total grounding sensor, 200-an analog signal conditioning module, 300-an analog-to-digital (AD) sampling module, 400-a control module, 410-a Fourier transform module, 420-a calibration module, 430-a calculation module, 440-a comparison module, 450-a fault recording module, 500-a communication module and 600-a storage module.

Detailed Description

To make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following examples and drawings, and the exemplary embodiments and descriptions thereof of the present invention are only used for explaining the present invention, and are not intended as limitations of the present invention.

Example 1

This embodiment 1 provides a sheath circulating current online monitoring device with fault recording, as shown in fig. 1, the device includes a signal acquisition module 100, an analog signal conditioning module 200, an AD sampling module 300, a storage module 600, a control module 400, and a communication module 500, which are sequentially connected along a current transmission direction, where the signal acquisition module 100 includes a load current sensor 110 for acquiring a cable current load and a three-phase circulating current sensor 120 for acquiring a cable circulating current, as shown in fig. 3, the signal acquisition module is an analog signal conditioning module, the analog signal conditioning module 200 is configured to condition and filter an acquired electrical signal, the AD sampling module 300 performs AD conversion on the electrical signal conditioned by the analog signal conditioning module 200 and transmits the electrical signal to the control module 400, the communication module 500 is configured to time-synchronize with a network, and the control module 400 is configured to calculate a three-phase circulating current value acquired by the three-phase circulating current sensor and a load current value acquired by the load current sensor The ratio of the current values, when a ground fault occurs, the control module 400 records the circulation waveform data of a plurality of ms before and a plurality of ms after the fault occurs, where the circulation waveform data are the three-phase circulation value and the load current value of the cable, and the control module 400 sends the circulation waveform data to the storage module 600 for recording the circulation fault recording data of the cable. Specifically, when the protection device at a certain position of the cable judges that a ground fault occurs (when the electric signal acquired by the signal acquisition module is judged to be a ground fault by the control module), the control module records three-phase and load waveforms of 200ms before and 800ms after the fault occurs, and meanwhile, the control module 400 sends a broadcast command (trigger signal) to enable the storage module of the whole cable to record circulating current waveform data at the same time, so that the fault analysis of the whole cable system is facilitated.

In the embodiment, the three-phase circulation sensor is a circulation sensor (an A-phase circulation sensor, a B-phase circulation sensor and a C-phase circulation sensor) for detecting a three-phase cable, the circulation sensor adopts a Hall current sensor, and the Hall current sensor has the characteristics of high response speed and magnetic saturation resistance; the load current sensor adopts a flexible Rogowski coil, so that the installation of a main cable is facilitated. The Rogowski coil is an alternating current sensor, is a hollow annular coil, has two types of flexibility and rigidity, and can be directly sleeved on a conductor to be measured to measure alternating current. The Rogowski coil is suitable for measuring alternating current in a wide frequency range, has no special requirements on conductors and sizes, has quick instant response capability, is widely applied to occasions where the traditional current measuring device such as a current transformer cannot be used, and is used for current measurement, particularly high-frequency and large-current measurement.

As shown in fig. 4, in the present embodiment, the communication module 500 includes an ethernet chip U31 and peripheral circuits of the ethernet chip. The communication module adopts an Ethernet (PHY) chip supporting the PTP network time synchronization to accurately time. The model of the Ethernet chip U31 is KSZ8041TL or KSZ8041 FTL. Through accurate PTP timing (time synchronization) combined with all-line fault recording, the all-dimensional waveform of the fault is recorded, and fault analysis is convenient to perform. Here, the PTP pair and the fault recording are also the prior art, and reference may be made to "CN 201520716623.9 intelligent substation network message analysis and fault recording system".

In this embodiment, the storage module 600 is a CPU memory, and the storage module 600 is connected to the control module 400, and is configured to store the configuration of the circulation system and circulation wave recording data. Specifically, the storage module is mainly used for storing various configurations of the circulation system and circulation recording files adopting a common standard COMTRADE format.

In this embodiment, the protection device further includes an IO module 700, the IO module is connected to the control module 400, and the control module 400 transmits a protection signal corresponding to the ground fault to the external cable protection device through the IO module 700. Specifically, the IO module 700 mainly includes a plurality of relays, and the relays are disposed in a start circuit of the cable protection device and used for signal linkage of ground fault alarm. The signal linkage of the ground fault alarm means that when a ground fault occurs at a certain position of the cable, the control module sends a control signal to control the corresponding relay to act so as to start the corresponding cable protection device to protect the cable.

In this embodiment, the signal acquisition module 100 further includes a temperature sensor 130, and the temperature sensor 130 is configured to acquire a temperature of the cable joint.

In this embodiment, the signal acquisition module 100 further includes a total ground sensor 140, and the total ground sensor 140 is configured to acquire a ground current value of the sheath.

As shown in fig. 2, in the present embodiment, the AD sampling module includes a sampling chip U34 and a sampling peripheral circuit.

In this embodiment, the control module 400 includes a fourier transform module 410, a calibration module 420, a calculation module 430, a comparison module 440, and a fault recording module 450, which are sequentially connected along a current transmission direction, the control module 400 is an MCU, an input end of the fourier transform module 410 is connected to the AD sampling module 300, the fault recording module 450 is respectively connected to the storage module 600 and the communication module 500, the fourier transform module 410 is configured to perform fourier transform on a three-phase circulating current value transmitted by the AD sampling module 300 to obtain an amplitude and a phase of a power frequency partial signal of the three-phase circulating current value, the calibration module 420 is configured to calibrate the three-phase circulating current value to obtain a three-phase phasor of the three-phase circulating current value, the calculation module 430 is configured to calculate an effective three-phase phasor to obtain a zero-sequence phasor (zero-sequence current), the comparison module 440 is configured to compare the three-phase phasor with the load current value to obtain a ratio, the fault recording module 450 is configured to determine whether to perform fault recording according to the size of the ratio, and execute fault recording or no fault recording according to a determination result.

Specifically, an electric signal acquired by an external sensor is subjected to signal conditioning and filtering, is converted into a digital signal through An (AD) sampling chip, the digital signal is sampled to a control module signal, firstly, the amplitude and the phase of a power frequency part signal are obtained through Fourier transform, an effective three-phase phasor is finally obtained through a calibration link of a three-phase circulation value, a zero-sequence phasor (zero-sequence current) can be obtained through calculation, the three-phase phasor and the zero-sequence phasor are subjected to mutation protection logic and are combined with the ratio of the three-phase phasor to load current, circulation earth faults are comprehensively judged, and corresponding fault recording is carried out through a fault recording module.

For the grounding fault, the occurrence of the fault can be judged better by the three-phase voltage bias caused by grounding and the generated zero-sequence current compared with the simple split-phase current, and meanwhile, partial false alarm is also avoided by combining the comprehensive judgment of the load current ratio of each phase of current. The fault recording of the whole cable also has a systematic judgment basis for the pre-cause result of the occurrence of the ground fault, so that technicians can conveniently judge the position and the type of the occurrence of the ground fault through experience.

When the cable runs at full load in summer, the three-phase phasor of the cable circulation becomes large, meanwhile, the load current also becomes large, and if no ground fault occurs, the ratio of the three-phase phasor to the load current does not exceed the set threshold; when the ratio of the three-phase phasor to the load current is greater than a set threshold value, a circulating earth fault can be determined.

The amplitude and the phase of the electric signal obtained by converting the electric signal through the fourier module are the prior art, and reference can be made to the prior art "an extraction method of the unbalanced component of the micro-differential double-rotor system based on frequency spectrum correction" and "an online detection and filtering method of the subsynchronous oscillation component of the CN201610008784.1 power system";

the calibration of the three-phase phasor of the three-phase circulating current value by the calibration module is also the prior art, and reference can be made to the prior art "CN 88214519.3 self-calibration three-phase voltage adjusting device" or "a calculation method of a voltage included angle and a zero line current of cn201911125128. x" and a three-phase electric energy meter ";

the technology of calculating (decomposing) three-phase phasor into zero-sequence phasor through a calculation module is also the prior art, and reference can be made to the prior art "measurement method and measurement device of CN201510607025.2 subsynchronous and supersynchronous harmonic phasors";

the comparison module compares the three-phase phasor with the load current value to obtain a ratio which is the prior art, the comparison module can adopt a comparator and a corresponding peripheral circuit, and the comparison module is set by a person skilled in the art according to actual conditions and is the prior art, and the comparison module is not repeated;

here, the abrupt change amount protection is also the prior art, for example, "CN 202010293745.7 dc line abrupt change amount protection control method, apparatus, system and storage medium" discloses that "in a multi-terminal dc transmission system, including three or more dc terminals, in order to protect the multi-terminal dc transmission system, a mechanism for setting corresponding protection is required to trigger a protection action under a specific condition, and protect the system in time, for example, the straight line abrupt change amount protection is used for detecting a ground fault of a dc line, and starting the dc line abrupt change amount protection can make the system enter a line fault restart logic, and enter a subsequent restart control, and protect the system. "and the skilled person can apply the abrupt amount protection to the three-phase phasor in the alternating current by referring to the technology, without involving the improvement of the computer program.

The above-mentioned embodiments, further detailed description of the objects, technical solutions and advantages of the present invention, it should be understood that the above description is only the embodiments of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. The protective layer circulation on-line monitoring device with fault recording is characterized by comprising a signal acquisition module, an analog signal conditioning module, an AD sampling module, a storage module, a control module and a communication module which are sequentially connected along a current transmission direction, wherein the signal acquisition module comprises a load current sensor for acquiring a cable current load and a three-phase circulation sensor for acquiring cable circulation, the analog signal conditioning module is used for filtering acquired electric signals, the AD sampling module is used for AD converting the electric signals conditioned by the analog signal conditioning module and transmitting the electric signals to the control module, the communication module is used for time synchronization with a network, the control module is used for calculating the ratio of a three-phase circulation value acquired by the three-phase circulation sensor to a load current value acquired by the load current sensor, when a ground fault occurs, the control module records circulation waveform data of a plurality of ms before and a plurality of ms after the fault occurs, and transmits the circulation waveform data to the storage module.

2. The device for monitoring sheath circulating current with fault recording of claim 1, wherein the communication module comprises an ethernet chip U31 and a peripheral circuit of the ethernet chip.

3. The on-line sheath circulating current monitoring device with fault recording function as claimed in claim 1, wherein the storage module is a CPU memory for storing circulating current recording data.

4. The device for on-line monitoring of sheath circulating current with fault recording of claim 1, further comprising an IO module, wherein the IO module is connected with the control module, and the control module transmits a protection signal corresponding to a ground fault to an external cable protection device through the IO module.

5. The device for on-line monitoring of sheath circulating current with fault recording of claim 4, wherein the IO module comprises a plurality of relays connected with an external cable protection device.

6. The on-line sheath loop current monitoring device with fault recording function as claimed in claim 1, wherein said signal acquisition module further comprises a temperature sensor, said temperature sensor is used for acquiring temperature of cable joint.

7. The on-line sheath circulating current monitoring device with fault recording function as claimed in claim 1, wherein said signal collecting module further comprises a total grounding sensor, said total grounding sensor is used for collecting grounding current value of cable sheath.

8. The on-line sheath loop current monitoring device with fault recording function as claimed in claim 1, wherein said AD sampling module comprises a sampling chip U34 and a sampling peripheral circuit.

9. The on-line sheath circulating current monitoring device with fault recording function of claim 1, wherein the control module comprises a fourier transform module, a calibration module, a calculation module, a comparison module and a fault recording module, which are sequentially connected along a current transmission direction, an input end of the fourier transform module is connected to the AD sampling module, the fault recording module is respectively connected to the storage module and the communication module, the fourier transform module is configured to perform fourier transform on a three-phase circulating current value transmitted by the AD sampling module to obtain an amplitude value and a phase value of a power frequency part signal of the three-phase circulating current value, the calibration module is configured to calibrate the three-phase circulating current value to obtain a three-phase phasor of the three-phase circulating current value, the calculation module is configured to calculate an effective three-phase phasor to obtain a zero-sequence phasor, the comparison module is configured to compare the three-phase phasor with the load current value to obtain a ratio, and the fault recording module is used for judging whether to carry out fault recording according to the ratio and executing fault recording or not according to the judgment result.

10. The on-line sheath loop current monitoring device with fault recording function as claimed in claim 1, wherein the loop current waveform data is three-phase loop current value and load current value of the cable.

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