1. Partial discharge live-line inspection system suitable for open-type transformer substation, its characterized in that: including the signal processing module that connects gradually, signal switching module, signal acquisition module, communication module and host computer, signal processing module electric connection has power frequency signal conditioning module and superfrequency signal conditioning module, power frequency signal conditioning module electric connection has power frequency induction sensor, superfrequency signal conditioning module electric connection has superfrequency sensor A and superfrequency sensor B, superfrequency signal conditioning module and signal switching module, the equal electric connection of signal acquisition module.

2. The partial discharge live inspection system suitable for the open-type substation of claim 1, wherein: the ultrahigh frequency signal conditioning module comprises a first signal amplification submodule, a signal attenuation submodule, a second signal amplification submodule and a signal detection submodule which are electrically connected in sequence, the ultrahigh frequency sensor A and the ultrahigh frequency sensor B are electrically connected with the first signal amplification submodule, the signal acquisition module and the signal switching module are electrically connected with the second signal amplification submodule, and the signal processing module is electrically connected with the signal attenuation submodule and the signal detection submodule.

3. The partial discharge live inspection system suitable for the open-type substation of claim 2, wherein: the signal processing module comprises a first AD acquisition submodule, a second AD acquisition submodule and an instruction receiving submodule, the first AD acquisition submodule is electrically connected with the power frequency signal conditioning module, the first AD acquisition submodule is sequentially connected with a zero crossing point extraction submodule and a sawtooth wave output submodule, the sawtooth wave output submodule is electrically connected with the signal switching module, the second AD acquisition submodule is electrically connected with the signal detection submodule, the second AD acquisition submodule is sequentially connected with a signal amplitude value calculation submodule and an attenuation control judgment submodule, and the attenuation control judgment submodule and the signal attenuation submodule, the communication modules are all electrically connected, the instruction receiving submodule is electrically connected with the communication modules, the instruction receiving submodule is electrically connected with the signal switching control submodule, and the signal switching control submodule is electrically connected with the signal switching module.

4. The live inspection method for partial discharge suitable for the open type transformer substation is based on the live inspection system for partial discharge suitable for the open type transformer substation of claim 3, a partial discharge source and an antenna array are arranged in the open type transformer substation, the antenna array comprises two antennas, and the live inspection method is characterized in that: the inspection method comprises the following steps:

s1, the ultrahigh frequency sensor A and the ultrahigh frequency sensor B acquire ultrahigh frequency electromagnetic wave signals to obtain a first signal and a second signal, the first signal and the second signal are transmitted to the ultrahigh frequency signal conditioning module, the power frequency induction sensor acquires power frequency signals, and the power frequency signals are transmitted to the power frequency signal conditioning module;

s2, the ultrahigh frequency signal conditioning module conditions the first signal and the second signal to obtain a first conditioning signal x_A(n), a second conditioning signal x_B(n) and a detection signal, and a power frequency signal conditioning module conditions the power frequency signal to obtain a power frequency square wave;

s3, mixing the first conditioning signal x_A(n), a second conditioning signal x_B(n) respectively sending the detection signal and the power frequency square wave to the signal processing module by the signal acquisition module and the signal switching module;

s4, the signal processing module adjusts the ultrahigh frequency signal conditioning module according to the detection signal, processes the power frequency square wave to obtain a sawtooth wave signal g (n), and sends the sawtooth wave signal g (n) to the signal acquisition module;

s5, setting a detection mode of the upper computer, executing S6-S9 if the detection mode is a positioning mode, and executing S10-S13 if the detection mode is a map analysis mode;

s6, acquiring a second conditioning signal x by the signal acquisition module_B(n) and applying the first conditioning signal x_A(n) and a second conditioning signal x_B(n) sending to an upper computer;

s7, for the first conditioning signal x_A(n) and a second conditioning signal x_B(n) performing interpolation to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n)；

S8, calculating a first interpolation signal S_A(n) and a second interpolation signal s_B(n) time difference Δ t;

s9, calculating an azimuth angle theta of the local discharge source relative to the antenna array according to the time difference delta t, and judging the position of the local discharge source relative to the antenna array;

s10, the signal acquisition module acquires a sawtooth wave signal g (n) and a first conditioning signal x_A(n) and a sawtooth wave signal g (n) are sent to an upper computer;

s11, calculating a first conditioning signal x_A(n) corresponding power frequency phase

S12, calculating a first conditioning signal x_A(n) the pulse signal power Y of the effective signal;

s13, the upper computer according to the power frequency phaseAnd the pulse signal power Y is displayed in a map.

5. The partial discharge live inspection method suitable for the open-type substation according to claim 4, wherein: the specific steps of S4 are:

s401, detecting a detection signal by a second AD acquisition module, and calculating the amplitude of the detection signal by a signal amplitude value operator module;

s402, when the amplitude of the detection signal is smaller than a preset amplitude threshold value, controlling an attenuation control judgment submodule to send an instruction to a signal attenuation submodule, and reducing the attenuation multiple of the signal attenuation submodule;

s403, the first AD acquisition module acquires the power frequency square wave, and the zero crossing point extraction submodule acquires the zero crossing point position of the rising edge of the power frequency square wave;

s404, taking the zero-crossing position as a starting point, generating and outputting a sawtooth wave signal g (n) by the sawtooth wave output module to the signal switching module, wherein the signal amplitude of the sawtooth wave signal g (n) is U.

6. The partial discharge live inspection method suitable for the open-type substation according to claim 5, wherein: the specific method of S7 is as follows: the upper computer receives a first conditioning signal x_A(n) and a second conditioning signal x_B(n) applying cubic spline interpolation method to the first conditioning signal x_A(n) and a second conditioning signal x_B(n) performing interpolation to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n)。

7. The live partial discharge inspection method suitable for the open-type substation according to claim 6, wherein: the specific steps of S8 are:

s801, calculating a first interpolation signal S_AMinimum cumulative energy E of (n)_min(n) obtaining a minimum accumulated energy curve, and obtaining a sampling point number χ corresponding to the minimum value of the minimum accumulated energy curve:

wherein N is the first conditioning signal x_A(n), E (n) is the first conditioning signal x_A(n) an energy accumulation curve, n being the first conditioning signal x_A(n) ordinal number, s²(q) is s_A ²(n), q is the number of counts in the calculation of the energy accumulation curve, E_NIs the maximum of the energy accumulation curve E (n);

s802, according to the signal sampling rate, taking χ' as the first interpolation signal S_A(n) taking χ '+ 40 or χ' +80 as the interception length to obtain the first waveband s_A' (n), wherein χ ' - χ -4 or χ ' - χ -9;

s803, to S_A' (n) are smoothed to obtain a first filtered signal s_A”(n)；

S804, based on S_A"(n) maximum value sets signal threshold, statistics s_A"(n) peak and trough positions, searching zero-crossing points between the peak and the trough, and corresponding time t with the first zero-crossing point and the third zero-crossing point_cro1And t_cro3As the interception position of the head wave, in the first interpolation signal s_A(n) intercepting the head wave, sequentially supplementing 0 before and after intercepting the head wave to obtain sum s_A(n) equal length signals, i.e. the first interpolated signal s_A(n) head wave s_{wh_A}(n)；

S805, repeating S801 to S804 to obtain a second interpolation signal S_B(n) head wave s_{wh_B}(n)；

S806, according to S_{wh_A}(n) and s_{wh_B}(n) performing time delay estimation by using a cross-correlation algorithm to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n) time difference Δ t.

8. The partial discharge live inspection method suitable for the open-type substation according to claim 7, wherein: the specific method of S9 is as follows: calculating the azimuth angle theta of the partial discharge source relative to the antenna array:

where c is the propagation speed of the electromagnetic wave and L is the distance between the two antennas.

9. The live partial discharge inspection method suitable for the open-type substation according to claim 8, wherein: the specific method of S11 is as follows: first conditioning signal x_A(n) corresponding power frequency phase

Wherein N is x_A(n) total number of points, n being x_AThe ordinal number of discrete points in (n), U, is the signal amplitude of the sawtooth wave signal g (n).

10. The live partial discharge inspection method suitable for the open-type substation according to claim 9, wherein: the specific steps of S12 are:

s1201, calculating a first conditioning signal x_A(n) minimum ofIntegrating energy to obtain x_A(n) minimum cumulative energy curve;

s1202, extracting a first conditioning signal x_A(n) starting point position x_{beg_loc}；

S1203, first conditioning signal x_A(n) performing a Hilbert transform to obtain a first conditioned signal x_AEnvelope x of (n)_{A_Env}(n)；

S1204, extracting envelope x_{A_Env}X of (n)_{beg_loc}Envelope amplitude x of_{beg_amp}At an envelope amplitude x_{beg_amp}For the envelope threshold, extract envelope x_{A_Env}(n) end point position x corresponding to falling edge_{end_loc}；

S1205, intercepting the first conditioning signal x_A(n) an envelope amplitude x_{beg_amp}And end point position x_{end_loc}Signal segment x in between_{A_seg}(m), signal segment x_{A_seg}(m) is a valid signal;

s1206, calculating the effective signal x_{A_seg}Pulse signal power Y of (m):

wherein M is x_{A_seg}(m) total number of points, m being x_{A_seg}(m) ordinal number of discrete points.

Background

The current state detection aiming at the electrical equipment of the whole substation is divided into two types: power failure detection and live detection. The live detection technology does not influence the overall operation of the transformer substation in the detection process, and is comprehensively applied in recent years. Partial discharge detection of electrical equipment of a substation is an important component in live-line detection content. The types and the quantity of equipment in the open-type transformer substation are numerous, and the insulation between the equipment is mainly air, so that the common partial discharge live detection equipment is mainly used for detecting based on an ultrahigh frequency method. The partial discharge detection equipment of the ultrahigh frequency method mainly comprises two types, namely partial discharge detection equipment based on atlas analysis and partial discharge source positioning equipment.

The principle of the detection equipment based on the map is to obtain a PRPD (phase-resolved partial discharge)/PRPS (phase-resolved pulse sequence) map of partial discharge and analyze and diagnose the type of the partial discharge through the map, and the main equipment of the detection equipment of the type is a PDS100 type ultrahigh frequency partial discharge inspection instrument of Doble company in America, a series product thereof and a PD74i type partial discharge inspection instrument of Shanghai Lubu science and technology Limited. The equipment is usually a handheld equipment, is suitable for one person to operate, and the instrument architecture comprises two parts of hardware and software, wherein the hardware part comprises an ultrahigh frequency sensor and a signal conditioning and acquisition circuit, and the software part realizes the analysis and result presentation of signals. The signal conditioning circuit realizes the functions of signal amplification, filtering and detection, the duration of the detected signal is prolonged, the sampling frequency of the signal acquisition circuit can be effectively reduced, and the complexity of the system is reduced. However, in the application aspect, when the device is detected in the open-type substation, each device needs to be detected one by one, so that the problem of low efficiency exists, and the device with partial discharge cannot be accurately detected due to the dense devices.

The equipment for positioning the partial discharge source in the open-type substation generally adopts an omnidirectional ultrahigh-frequency antenna to form an antenna array, and positions the partial discharge source by using a detected array ultrahigh-frequency signal based on a TDOA algorithm, wherein the detection equipment is represented by a PDtect4 ultrahigh-frequency partial discharge detection positioning system of Haoglobu technologies, Inc. Because four antennas are needed for positioning the partial discharge source, an automobile load antenna array is usually used for detection in a substation, and at least two persons are usually required to operate cooperatively. The architecture of such systems also includes both hardware and software components. The hardware part comprises four ultrahigh frequency sensors, a signal conditioning circuit, a signal acquisition device and an antenna array supporting structure, and the software part realizes the positioning of a signal source based on a TDOA algorithm or other algorithms. The signal conditioning circuit realizes the filtering and amplification of signals, and the signal acquisition module has the function of four-path high-speed acquisition and realizes the synchronous acquisition of four-path ultrahigh-frequency signals. The positioning device has higher requirements on the signal acquisition module than the atlas-based detection device, and generally requires a sampling rate of the signal acquisition device of several gigahertz or even higher. Therefore, the local discharge positioning device cannot directly realize the function of map detection due to the overhigh sampling rate. Meanwhile, the vehicle-mounted partial discharge detection device used in the open-type transformer substation cannot go deep into an equipment dense area for detection due to overlarge size of a vehicle, so that the detection range in the transformer substation is limited, and meanwhile, an ultrahigh frequency signal generated by partial discharge generated inside the equipment overflowing to an external space is very weak, so that an effective signal cannot be detected due to the fact that the vehicle-mounted detection device cannot perform short-distance detection, and the detection sensitivity of the system is reduced.

In conclusion, the signal sampling rate of the map analysis type partial discharge detection equipment is low, in order to achieve continuous signal acquisition, the time domain waveform of a signal is conditioned in the signal conditioning stage to be distorted, the problem of low efficiency exists in detection in an open type transformer substation, and a real time domain signal cannot be obtained. The partial discharge positioning equipment needs to be detected in an open type transformer substation in a vehicle-mounted mode, and the problems that the detection range is limited, the sensitivity is low, and a PRPD/PRPS map cannot be directly obtained exist.

Disclosure of Invention

In order to solve the defects in the prior art, the invention provides the partial discharge live inspection system and the partial discharge live inspection method suitable for the open-type transformer substation, the inspection system is simple in structure, the inspection system is used according to the inspection method, the positioning of a partial discharge source can be realized, the PRPD/PRPS atlas can be analyzed, the field detection efficiency of the open-type transformer substation is improved, and the practicability of the system is increased.

In order to achieve the purpose, the invention provides the following technical scheme: the partial discharge live inspection system suitable for the open-type transformer substation comprises a signal processing module, a signal switching module, a signal acquisition module, a communication module and an upper computer which are sequentially connected, wherein the signal processing module is electrically connected with a power frequency signal conditioning module and an ultrahigh frequency signal conditioning module, the power frequency signal conditioning module is electrically connected with a power frequency induction sensor, the ultrahigh frequency signal conditioning module is electrically connected with an ultrahigh frequency sensor A and an ultrahigh frequency sensor B, and the ultrahigh frequency signal conditioning module is electrically connected with the signal switching module and the signal acquisition module.

As the further optimization of the partial discharge live inspection system suitable for the open-type substation: the ultrahigh frequency signal conditioning module comprises a first signal amplification submodule, a signal attenuation submodule, a second signal amplification submodule and a signal detection submodule which are electrically connected in sequence, the ultrahigh frequency sensor A and the ultrahigh frequency sensor B are electrically connected with the first signal amplification submodule, the signal acquisition module and the signal switching module are electrically connected with the second signal amplification submodule, and the signal processing module is electrically connected with the signal attenuation submodule and the signal detection submodule.

As the further optimization of the partial discharge live inspection system suitable for the open-type substation: the signal processing module comprises a first AD acquisition submodule, a second AD acquisition submodule and an instruction receiving submodule, the first AD acquisition submodule is electrically connected with the power frequency signal conditioning module, the first AD acquisition submodule is sequentially connected with a zero crossing point extraction submodule and a sawtooth wave output submodule, the sawtooth wave output submodule is electrically connected with the signal switching module, the second AD acquisition submodule is electrically connected with the signal detection submodule, the second AD acquisition submodule is sequentially connected with a signal amplitude value calculation submodule and an attenuation control judgment submodule, and the attenuation control judgment submodule and the signal attenuation submodule, the communication modules are all electrically connected, the instruction receiving submodule is electrically connected with the communication modules, the instruction receiving submodule is electrically connected with the signal switching control submodule, and the signal switching control submodule is electrically connected with the signal switching module.

The local discharge live inspection method suitable for the open-type transformer substation is based on the local discharge live inspection system suitable for the open-type transformer substation, a local discharge source and an antenna array are arranged in the open-type transformer substation, the antenna array comprises two antennas, and the inspection method comprises the following steps:

s1, the ultrahigh frequency sensor A and the ultrahigh frequency sensor B acquire ultrahigh frequency electromagnetic wave signals to obtain a first signal and a second signal, the first signal and the second signal are transmitted to the ultrahigh frequency signal conditioning module, the power frequency induction sensor acquires power frequency signals, and the power frequency signals are transmitted to the power frequency signal conditioning module;

s2, the ultrahigh frequency signal conditioning module conditions the first signal and the second signal to obtain a first conditioning signal x_A(n), a second conditioning signal x_B(n) and a detection signal, and a power frequency signal conditioning module conditions the power frequency signal to obtain a power frequency square wave;

s3, mixing the first conditioning signal x_A(n)、Second conditioning signal x_B(n) respectively sending the detected signal and the power frequency square wave to a signal processing module;

s4, the signal processing module adjusts the ultrahigh frequency signal conditioning module according to the detection signal, processes the power frequency square wave to obtain a sawtooth wave signal g (n), and sends the sawtooth wave signal g (n) to the signal acquisition module;

s5, setting a detection mode of the upper computer, executing S6-S9 if the detection mode is a positioning mode, and executing S10-S13 if the detection mode is a map analysis mode;

s6, acquiring a second conditioning signal x by the signal acquisition module_B(n) and applying the first conditioning signal x_A(n) and a second conditioning signal x_B(n) sending to an upper computer;

s7, for the first conditioning signal x_A(n) and a second conditioning signal x_B(n) performing interpolation to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n)；

S8, calculating a first interpolation signal S_A(n) and a second interpolation signal s_B(n) time difference Δ t;

s9, calculating an azimuth angle theta of the local discharge source relative to the antenna array according to the time difference delta t, and judging the position of the local discharge source relative to the antenna array;

s10, the signal acquisition module acquires a sawtooth wave signal g (n) and a first conditioning signal x_A(n) and a sawtooth wave signal g (n) are sent to an upper computer;

s11, calculating a first conditioning signal x_A(n) corresponding power frequency phase

S12, calculating a first conditioning signal x_A(n) the pulse signal power Y of the effective signal;

s13, the upper computer according to the power frequency phaseAnd the pulse signal power Y is displayed in a map.

As a further optimization of the above-described partial discharge live inspection method suitable for an open-type substation: the specific steps of S4 are:

s401, detecting a detection signal by a second AD acquisition module, and calculating the amplitude of the detection signal by a signal amplitude value operator module;

s402, when the amplitude of the detection signal is smaller than a preset amplitude threshold value, controlling an attenuation control judgment submodule to send an instruction to a signal attenuation submodule, and reducing the attenuation multiple of the signal attenuation submodule;

s403, the first AD acquisition module acquires the power frequency square wave, and the zero crossing point extraction submodule acquires the zero crossing point position of the rising edge of the power frequency square wave;

s404, taking the zero-crossing position as a starting point, generating and outputting a sawtooth wave signal g (n) by the sawtooth wave output module to the signal switching module, wherein the signal amplitude of the sawtooth wave signal g (n) is U.

As a further optimization of the above-described partial discharge live inspection method suitable for an open-type substation: the specific method of S7 is as follows: the upper computer receives a first conditioning signal x_A(n) and a second conditioning signal x_B(n) applying cubic spline interpolation method to the first conditioning signal x_A(n) and a second conditioning signal x_B(n) performing interpolation to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n)。

As a further optimization of the above-described partial discharge live inspection method suitable for an open-type substation: the specific steps of S8 are:

s801, calculating a first interpolation signal S_AMinimum cumulative energy E of (n)_min(n) obtaining a minimum accumulated energy curve, and obtaining a sampling point number χ corresponding to the minimum value of the minimum accumulated energy curve:

wherein N is the first conditioning signal x_A(n)E (n) is the first conditioning signal x_A(n) an energy accumulation curve, n being the first conditioning signal x_A(n) ordinal number, s²(q) is s_A ²(n), q is the number of counts in the calculation of the energy accumulation curve, E_NIs the maximum of the energy accumulation curve E (n);

s802, according to the signal sampling rate, taking χ' as the first interpolation signal S_A(n) taking χ '+ 40 or χ' +80 as the interception length to obtain the first waveband s_A' (n), wherein χ ' - χ -4 or χ ' - χ -9;

s803, to S_A' (n) are smoothed to obtain a first filtered signal s_A”(n)；

S804, based on S_A"(n) maximum value sets signal threshold, statistics s_A"(n) peak and trough positions, searching zero-crossing points between the peak and the trough, and corresponding time t with the first zero-crossing point and the third zero-crossing point_cro1And t_cro3As the interception position of the head wave, in the first interpolation signal s_A(n) intercepting the head wave, sequentially supplementing 0 before and after intercepting the head wave to obtain sum s_A(n) equal length signals, i.e. the first interpolated signal s_A(n) head wave s_{wh_A}(n)；

S805, repeating S801 to S804 to obtain a second interpolation signal S_B(n) head wave s_{wh_B}(n)；

S806, according to S_{wh_A}(n) and s_{wh_B}(n) performing time delay estimation by using a cross-correlation algorithm to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n) time difference Δ t.

As a further optimization of the above-described partial discharge live inspection method suitable for an open-type substation: the specific method of S9 is as follows: calculating the azimuth angle theta of the partial discharge source relative to the antenna array:

where c is the propagation speed of the electromagnetic wave and L is the distance between the two antennas.

As a further optimization of the above-described partial discharge live inspection method suitable for an open-type substation: the specific method of S11 is as follows: first conditioning signal x_A(n) corresponding power frequency phase

Wherein N is x_A(n) total number of points, n being x_AThe ordinal number of discrete points in (n), U, is the signal amplitude of the sawtooth wave signal g (n).

As a further optimization of the above-described partial discharge live inspection method suitable for an open-type substation: the specific steps of S12 are:

s1201, calculating a first conditioning signal x_AMinimum cumulative energy of (n) to obtain x_A(n) minimum cumulative energy curve;

s1202, extracting a first conditioning signal x_A(n) starting point position x_{beg_loc}；

S1203, first conditioning signal x_A(n) performing a Hilbert transform to obtain a first conditioned signal x_AEnvelope x of (n)_{A_Env}(n)；

S1204, extracting envelope x_{A_Env}X of (n)_{beg_loc}Envelope amplitude x of_{beg_amp}At an envelope amplitude x_{beg_amp}For the envelope threshold, extract envelope x_{A_Env}(n) end point position x corresponding to falling edge_{end_loc}；

S1205, intercepting the first conditioning signal x_A(n) an envelope amplitude x_{beg_amp}And end point position x_{end_loc}Signal segment x in between_{A_seg}(m), signal segment x_{A_seg}(m) is a valid signal;

s1206, calculating the effective signal x_{A_seg}Pulse signal power Y of (m):

wherein M is x_{A_seg}(m) total number of points, m being x_{A_seg}(m) ordinal number of discrete points.

The beneficial effects are that: the invention provides a partial discharge live inspection system and a partial discharge live inspection method suitable for an open-type transformer substation, the inspection system is simple in structure, the inspection system is used according to the inspection method, not only can the positioning of a partial discharge source be realized, but also the PRPD/PRPS map can be analyzed, the field detection efficiency of the open-type transformer substation is improved, and the practicability of the system is increased.

Drawings

FIG. 1 is a block diagram of an inspection system architecture;

FIG. 2 is a block diagram of a VHF conditioning module architecture;

FIG. 3 is a schematic circuit diagram of an UHF conditioning module;

FIG. 4 is a schematic circuit diagram of a power frequency signal conditioning module;

FIG. 5 is a block diagram of a signal processing module architecture;

FIG. 6 is a circuit diagram of a signal switching module;

fig. 7 is a schematic diagram of a power frequency signal transformation process.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Please refer to fig. 1 to 7, the partial discharge live inspection system suitable for the open-type transformer substation comprises a signal processing module, a signal switching module, a signal acquisition module, a communication module and an upper computer which are sequentially connected, wherein the signal processing module is electrically connected with a power frequency signal conditioning module and an ultrahigh frequency signal conditioning module, the power frequency signal conditioning module is electrically connected with a power frequency induction sensor, the ultrahigh frequency signal conditioning module is electrically connected with an ultrahigh frequency sensor a and an ultrahigh frequency sensor B, and the ultrahigh frequency signal conditioning module is electrically connected with the signal switching module and the signal acquisition module.

The working principle is as follows: and a local discharge source and an antenna array are arranged in the open-type transformer substation. The detection modes of the upper computer are a positioning mode and an atlas analysis mode, the positioning mode utilizes the ultrahigh frequency electromagnetic wave signals detected by the ultrahigh frequency sensor A and the ultrahigh frequency sensor B to obtain the positioning of the local discharge source relative to the antenna array, and the atlas analysis mode utilizes the local discharge signals detected by the ultrahigh frequency sensor A and the power frequency signals detected by the power frequency induction sensor to carry out atlas drawing. The ultrahigh frequency sensor A and the ultrahigh frequency sensor B acquire ultrahigh frequency electromagnetic wave signals to obtain a first signal and a second signal, the first signal and the second signal are sent to the ultrahigh frequency signal conditioning module to be conditioned to obtain a first conditioned signal and a second conditioned signal, the first conditioned signal is sent to the signal acquisition module, and the second conditioned signal is sent to the signal switching module; the power frequency induction sensor collects and sends a power frequency signal to the power frequency signal conditioning module, and the power frequency signal is conditioned by the power frequency signal conditioning module and then sent to the signal processing module for processing to obtain a sawtooth wave signal; after the upper computer sets a detection mode, the upper computer sends a detection mode instruction to the signal processing module through the communication module, the signal processing module controls the signal switching module to send a signal to the signal acquisition module according to the instruction, if the signal switching module is in a positioning mode, the signal switching module sends a second conditioning signal to the signal acquisition module, the signal acquisition module sends a first conditioning signal and a second conditioning signal to the upper computer, the upper computer processes the first conditioning signal and the second conditioning signal to obtain the positioning of a local discharge source relative to an antenna array, if the signal switching module is in a pattern analysis mode, the signal switching module sends a sawtooth wave signal to the signal acquisition module, the signal acquisition module sends the first conditioning signal and the sawtooth wave signal to the upper computer, and the upper computer processes the first conditioning signal and the sawtooth wave signal to obtain a PRPD/PRPS pattern.

The upper computer realizes the functions of data analysis and man-machine interaction and can be realized by a notebook computer, a smart phone and a tablet computer. The signal acquisition module at least has two synchronous high-speed acquisition channels, the sampling rate reaches more than 5GS/s, and the analog bandwidth reaches more than 1GHz, so that a PICO6404E type oscilloscope is adopted as the signal acquisition module, and the oscilloscope can convert analog signals into digital signals. The communication module can use a wired communication or wireless communication mode, the wired communication uses a USB concentrator with two USB interfaces as the communication module, the signal processing module and the signal acquisition module respectively use one USB interface, and the output USB interface of the concentrator is connected with an upper computer; the wireless communication mode uses a USB to wifi module, and a print server can be adopted.

The ultrahigh frequency signal conditioning module comprises a first signal amplification submodule, a signal attenuation submodule, a second signal amplification submodule and a signal detection submodule which are electrically connected in sequence, the ultrahigh frequency sensor A and the ultrahigh frequency sensor B are electrically connected with the first signal amplification submodule, the signal acquisition module and the signal switching module are electrically connected with the second signal amplification submodule, and the signal processing module is electrically connected with the signal attenuation submodule and the signal detection submodule.

The ultrahigh frequency sensor A and the ultrahigh frequency sensor B are used for receiving ultrahigh frequency electromagnetic wave signals generated by a local discharge source, and the detection frequency bands of the ultrahigh frequency sensor A and the ultrahigh frequency sensor B cover 400MHz-1.5 GHz. The first signal and the second signal are subjected to three-stage conditioning of amplification, attenuation and amplification, the first conditioning signal and the second conditioning signal are obtained after the last stage of amplification, the first conditioning signal is directly sent to the signal acquisition module, one part of the second conditioning signal is sent to the signal switching module, the other part of the second conditioning signal is output to the signal detection module to obtain a detection signal, and the detection signal is sent to the signal processing module.

The signal processing module comprises a first AD acquisition submodule, a second AD acquisition submodule and an instruction receiving submodule, the first AD acquisition submodule is electrically connected with the power frequency signal conditioning module, the first AD acquisition submodule is sequentially connected with a zero crossing point extraction submodule and a sawtooth wave output submodule, the sawtooth wave output submodule is electrically connected with the signal switching module, the second AD acquisition submodule is electrically connected with the signal detection submodule, the second AD acquisition submodule is sequentially connected with a signal amplitude value calculation submodule and an attenuation control judgment submodule, and the attenuation control judgment submodule and the signal attenuation submodule, the communication modules are all electrically connected, the instruction receiving submodule is electrically connected with the communication modules, the instruction receiving submodule is electrically connected with the signal switching control submodule, and the signal switching control submodule is electrically connected with the signal switching module.

The signal processing module can adopt STM32 series single-chip microcomputer. The sampling rate of the first AD acquisition submodule and the second AD acquisition submodule is required to reach more than 100kS/s, and the sawtooth wave output submodule has a DA output function. The power frequency signal is conditioned by the power frequency conditioning module to obtain a power frequency square wave, the first AD acquisition submodule acquires the power frequency square wave, the zero crossing point extraction submodule acquires the zero crossing point position of the power frequency square wave, and the sawtooth wave output submodule generates and outputs a sawtooth wave signal to the signal switching module according to the zero crossing point position; the second AD acquisition submodule acquires detection signals, the signal amplitude calculation submodule calculates the amplitude of the detection signals, the attenuation control judgment submodule judges the attenuation information of the signal attenuation submodule according to the amplitude, if the amplitude is smaller, an instruction is sent to the signal attenuation submodule, the attenuation multiple is reduced, and the amplification multiple of the ultrahigh frequency signal conditioning module is increased. The command receiving submodule is electrically connected with the communication module, the upper computer sends a detection mode command to the command receiving submodule through the communication module, the command receiving submodule sends the detection mode command to the signal switching control submodule, and the signal switching control submodule controls the signal switching module to send a second conditioning signal or a sawtooth wave signal to the signal acquisition module.

The local discharge live inspection method suitable for the open-type transformer substation is based on the local discharge live inspection system suitable for the open-type transformer substation, a local discharge source and an antenna array are arranged in the open-type transformer substation, the antenna array comprises two antennas, and the inspection method comprises the following steps:

s1, the ultrahigh frequency sensor A and the ultrahigh frequency sensor B acquire ultrahigh frequency electromagnetic wave signals to obtain a first signal and a second signal, the first signal and the second signal are transmitted to the ultrahigh frequency signal conditioning module, and the power frequency induction sensor acquires power frequency signals and transmits the power frequency signals to the power frequency signal conditioning module.

S2, the ultrahigh frequency signal conditioning module conditions the first signal and the second signal to obtain a first conditioning signal x_A(n), a second conditioning signal x_BAnd (n) and a detection signal, and the power frequency signal conditioning module conditions the power frequency signal to obtain a power frequency square wave.

The first signal and the second signal pass through a first signal amplification submodule, a signal attenuation submodule and a second signal amplification submodule, and the first signal is subjected to primary amplification, attenuation and secondary amplification to obtain a first conditioning signal x_A(n), after the second signal is subjected to the first stage of amplification, attenuation and second stage of amplification, a part of the second signal generates a second conditioning signal x_BAnd (n), the other part enters a signal detection submodule to obtain a detection signal. The power frequency signal conditioning module filters and amplifies the power frequency signal, the amplification factor is set to 10000 times, and the power frequency signal is directly amplified to saturation distortion to obtain a power frequency square wave.

S3, mixing the first conditioning signal x_A(n), a second conditioning signal x_BAnd (n) respectively sending the detection signal and the power frequency square wave to the signal processing module.

S4, the signal processing module adjusts the ultrahigh frequency signal conditioning module according to the detection signal, processes the power frequency square wave to obtain a sawtooth wave signal g (n), and sends the sawtooth wave signal g (n) to the signal acquisition module.

The specific steps of S4 are:

s401, the second AD acquisition module detects detection signals, and the signal amplitude calculation submodule calculates the amplitude of the detection signals.

S402, when the amplitude of the detection signal is smaller than a preset amplitude threshold value, the attenuation control judgment submodule is controlled to send an instruction to the signal attenuation submodule, and the attenuation multiple of the signal attenuation submodule is reduced.

The second signal is conditioned by the ultrahigh frequency signal conditioning module to obtain a second conditioned signal and a detection signal, the detection signal is sent to the second AD acquisition module, the signal amplitude calculation submodule calculates the amplitude of the detection signal, and when the attenuation control judgment submodule detects that the amplitude of the detection signal is smaller than the amplitude threshold value, the attenuation control judgment submodule is controlled to send an instruction to the signal attenuation submodule, namely, an attenuation control coefficient is sent, the attenuation multiple of the signal attenuation submodule is reduced, and the amplification multiple of the ultrahigh frequency signal conditioning module is increased.

S403, the first AD acquisition module acquires the power frequency square wave, and the zero crossing point extraction submodule acquires the position of the zero crossing point of the rising edge of the power frequency square wave.

S404, taking the zero-crossing position as a starting point, generating and outputting a sawtooth wave signal g (n) by the sawtooth wave output module to the signal switching module, wherein the signal amplitude of the sawtooth wave signal g (n) is U.

In fig. 7, the first line is a power frequency signal waveform, the second line is a power frequency square wave waveform, and the third line is a sawtooth wave signal waveform, the frequency of the sawtooth wave signal is the same as the frequency of the power frequency signal, and the signal amplitude U is a fixed value.

And S5, setting a detection mode of the upper computer, executing S6-S9 if the detection mode is a positioning mode, and executing S10-S13 if the detection mode is a map analysis mode.

The signal acquisition module adopts a PICO6404E type virtual oscilloscope, the sampling rate of the signal acquisition module is 10GS/s, the signal acquisition module can convert an analog signal into a digital signal, namely, signals sent to an upper computer by the signal acquisition module are all digital signals.

S6, acquiring a second conditioning signal x by the signal acquisition module_B(n) and applying the first conditioning signal x_A(n) and a second conditioning signal x_BAnd (n) sending the data to an upper computer.

S7, for the first conditioning signal x_A(n) and a second conditioning signal x_B(n) performing interpolation to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n)。

The specific method of S7 is as follows: the upper computer receives a first conditioning signal x_A(n) and a second conditioning signal x_B(n) applying cubic spline interpolation method to the first conditioning signal x_A(n) and a second conditioning signal x_B(n) performing interpolation to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n)。

The number of interpolation points is set to be 3, and the sampling rate after interpolation is equivalent to 40 GS/s.

S8, calculating a first interpolation signal S_A(n) and a second interpolation signal s_B(n) time difference Δ t.

The specific steps of S8 are:

s801, calculating a first interpolation signal S_AMinimum cumulative energy E of (n)_min(n) obtaining a minimum accumulated energy curve, and obtaining a sampling point number χ corresponding to the minimum value of the minimum accumulated energy curve:

wherein N is the first conditioning signal x_A(n), E (n) is the first conditioning signal x_A(n) an energy accumulation curve, n being the first conditioning signal x_A(n) ordinal number, s²(q) is s_A ²(n), q is the number of counts in the calculation of the energy accumulation curve, E_NThe maximum value of the energy accumulation curve e (n).

S802, according to the signal sampling rate, taking χ' as the first interpolation signal S_A(n) taking χ '+ 40 or χ' +80 as the interception length to obtain the first waveband s_A' (n), wherein χ ' - χ -4 or χ ' - χ -9.

S803, to S_A' (n) are smoothed to obtain a first filtered signal s_A”(n)。

S804, based on S_A"(n) maximum value sets signal threshold, statistics s_A"(n) peak and trough positions, searching zero-crossing points between the peak and the trough, and corresponding time t with the first zero-crossing point and the third zero-crossing point_cro1And t_cro3As the interception position of the head wave, in the first interpolation signal s_A(n) intercepting the head wave, and intercepting the head waveSequentially adding 0 to obtain the sum of s_A(n) equal length signals, i.e. the first interpolated signal s_A(n) head wave s_{wh_A}(n)。

In S804, S is_A"(n) 20% of the maximum value as the signal threshold.

S805, repeating S801 to S804 to obtain a second interpolation signal S_B(n) head wave s_{wh_B}(n)。

S806, according to S_{wh_A}(n) and s_{wh_B}(n) performing time delay estimation by using a cross-correlation algorithm to obtain a first interpolation signal s_A(n) and a second interpolation signal s_B(n) time difference Δ t.

And S9, calculating the azimuth angle theta of the local discharge source relative to the antenna array according to the time difference delta t, and judging the position of the local discharge source relative to the antenna array.

The specific method of S9 is as follows: calculating the azimuth angle theta of the partial discharge source relative to the antenna array:

where c is the propagation velocity of the electromagnetic wave, where c is 3 × 10⁸m/s, L is the distance between the two antennas.

And transforming the detection position for multiple times, repeating the steps from S1 to S9 to obtain multiple azimuth angles, and judging the position of the local discharge source relative to the antenna array according to the azimuth angles.

S10, the signal acquisition module acquires a sawtooth wave signal g (n) and a first conditioning signal x_AAnd (n) and a sawtooth wave signal g (n) are sent to an upper computer.

S11, calculating a first conditioning signal x_A(n) corresponding power frequency phase

The specific method of S11 is as follows: first conditioning signal x_A(n) corresponding power frequency phase

Wherein N is x_A(n) total number of points, n being x_AThe ordinal number of discrete points in (n), U, is the signal amplitude of the sawtooth wave signal g (n).

S12, calculating a first conditioning signal x_A(n) pulse signal power Y of the effective signal.

First, for the first conditioning signal x_A(n) carrying out amplitude reduction, and carrying out control on the attenuation control coefficient sent by the attenuation control judgment submodule and the amplification factor of the ultrahigh frequency signal conditioning module to the first conditioning signal x_A(n) performing amplitude reduction, and then calculating the pulse signal power Y of the effective signal.

The specific steps of S12 are:

s1201, calculating a first conditioning signal x_AMinimum cumulative energy of (n) to obtain x_A(n) minimum cumulative energy curve.

S1202, extracting a first conditioning signal x_A(n) starting point position x_{beg_l}oc。

S1203, first conditioning signal x_A(n) performing a Hilbert transform to obtain a first conditioned signal x_AEnvelope x of (n)_{A_Env}(n)。

S1204, extracting envelope x_{A_Env}X of (n)_{beg_loc}Envelope amplitude x of_{beg_amp}At an envelope amplitude x_{beg_amp}For the envelope threshold, extract envelope x_{A_Env}(n) end point position x corresponding to falling edge_{end_loc}。

S1205, intercepting the first conditioning signal x_A(n) an envelope amplitude x_{beg_amp}And end point position x_{end_loc}Signal segment x in between_{A_seg}(m), signal segment x_{A_seg}(m) is a valid signal. The effective signal extracted here is the first conditioned signal x_A(n) the pulse signal.

S1206, calculating the effective signal x_{A_seg}Pulse signal power Y of (m):

wherein M is x_{A_seg}(m) total number of points, m being x_{A_seg}(m) ordinal number of discrete points.

S13, the upper computer according to the power frequency phaseAnd the pulse signal power Y is displayed in a map.

The profile shown is a PRPD/PRPS profile, after which the first conditioning signal x is added_AAnd (n) performing background storage on the sawtooth wave signals g and n, establishing an index relation with each pulse signal in the PRPD map, and realizing presentation and subsequent analysis of the corresponding partial discharge original ultrahigh frequency electromagnetic wave signals through selection of the pulse signals in the map.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.