Non-contact live detection apparatus and live detection method

A detection method, being applied to a non-contact detection apparatus for an insulation defect of overhead power lines for power distribution, wherein the non-contact detection apparatus comprises a processing unit, a detection unit and an image collection unit, the detection unit and the image collection unit communicatively connected to the processing unit;

• wherein the detection unit comprises an electromagnetic wave sensor and at least three ultrasonic sensors;
• the image collection unit is configured to collect an insulation defect picture of an overhead power line detected by the detection unit;
• and the processing unit is configured to obtain spatial coordinates of an insulation defect location, two-dimensional pixel coordinates of the insulation defect location, an electromagnetic wave intensity of the insulation defect location, and an ultrasonic intensity of the insulation defect location according to a detection result of the detection unit, and perform identification on the insulation defect picture;
• wherein the detection method comprises:
• detecting, by the detection unit of the detection apparatus, an overhead power line, and collecting, by the image collection unit of the detection apparatus, an image of the overhead power line in a predetermined direction to obtain the insulation defect picture;
• obtaining spatial coordinates of an insulation defect location, two-dimensional pixel coordinates of the insulation defect location, an electromagnetic wave intensity of the insulation defect location, and an ultrasonic intensity of the insulation defect location according to a detection result of the detection unit;
• and
• performing identification on the insulation defect picture according to the spatial coordinates, the two-dimensional pixel coordinates, the electromagnetic wave intensity, and the ultrasonic intensity;
• wherein obtaining the spatial coordinates of the insulation defect location and the two-dimensional pixel coordinates of the insulation defect location according to the detection result of the detection unit comprises:
• obtaining a distance between the insulation defect location and each of the at least three ultrasonic sensors according to a detection result of the electromagnetic wave sensor and detection results of the at least three ultrasonic sensors;
• obtaining the spatial coordinates of the insulation defect location according to the distance between the insulation defect location and each of the at least three ultrasonic sensors and a distance between adjacent ultrasonic sensors of the at least three ultrasonic sensors;
• and
• transforming the spatial coordinates of the insulation defect location into the pixel coordinates according to a parameter of the image collection unit;
• wherein obtaining the distance between the insulation defect location and each of the at least three ultrasonic sensors according to the detection result of the electromagnetic wave sensor and the detection results of the at least three ultrasonic sensors comprises:
• acquiring electromagnetic signals detected by the electromagnetic wave sensor and ultrasonic signals detected by the at least three ultrasonic sensors;
• performing extraction on the electromagnetic signals and the ultrasonic signals to obtain corresponding arrival moments of the electromagnetic signals and corresponding arrival moments of the ultrasonic signals, separately;
• determining a delay between the electromagnetic signals and the ultrasonic signals based on a discharge characteristic of the insulation defect location, the arrival moments of the electromagnetic signals and the arrival moments of the ultrasonic signals;
• and
• obtaining the distance between the insulation defect location and each of the at least three ultrasonic sensors based on the delay between the electromagnetic signals and the ultrasonic signals;
• wherein determining the delay between the electromagnetic signals and the ultrasonic signals based on the discharge characteristic of the insulation defect location, the arrival moments of the electromagnetic signals and the arrival moments of the ultrasonic signals comprises:
• obtaining a plurality of delay increase intervals according to the arrival moments of the electromagnetic signals, the arrival moments of the ultrasonic signals, and a preset minimum delay resolution;
• determining, based on the plurality of delay increase intervals, a delay increase interval in which an estimated value of the delay is located;
• determining a corresponding arrival moment of the electromagnetic signals and a corresponding arrival moment of the ultrasonic signals according to the determined delay increase interval;
• and
• obtaining the delay between the electromagnetic signals and the ultrasonic signals according to the determined arrival moment of the electromagnetic signals and the determined arrival moment of the ultrasonic signals.