Novel cable insulation online detection apparatus

Abstract

The invention discloses a novel cable insulation online detection apparatus. The apparatus comprises a signal source, a current sensor, a voltage sensor, a signal conditioning circuit and a main controller, the signal source is used for loading low-frequency and low-voltage detection signals to a power grid formed by cables, the current sensor and the voltage sensor are used for obtaining low-frequency current signals and low-frequency voltage signals of each branch cable in the power grid, the signal conditioning circuit is used for amplifying and filtering the low-frequency current signals and the low-frequency voltage signals, and the main controller is connected with the signal conditioning circuit and used for processing the low-frequency current signals and the low-frequency voltage signals to obtain insulation parameters of the branch cables. According to the apparatus, real-time detection of the insulation aging states of the cables can be realized, early warning is given in advance when the insulation aging condition of the cable is serious, and new cables can be replaced in time to eliminate hidden risks of faults.

Description

technical field [0001] The invention relates to the technical field of power equipment, in particular to a novel cable insulation on-line detection device. Background technique [0002] Polyethylene cables have good electrical properties, safe and reliable operation; the cables have strong corrosion resistance and acid and alkali capabilities, simple installation and use methods, and hardly require any maintenance. These characteristics have great advantages over traditional cables. sex. At present, polyethylene cables have basically replaced other types of cables in various industries. Polyethylene cables have been widely used at home and abroad, and are still developing. For example, in Japan, 750kV high-voltage polyethylene cables have been developed and tested, and in Russia, the running time of 220kV polyethylene cables has reached for more than ten years. my country has also begun to use 220kV polyethylene cables, and the project of 500kV cables has also begun const...

AI Technical Summary

Problems solved by technology

[0003] However, during the use of polyethylene cables, cable insulation aging will occur due to external conditions, such as figure 1 As shown, the external electric field, heat, mechanical force, and water will form air gaps, local high voltages, and impurities in the air gaps on the cables, which will cause partial discharge aging, electrical tree aging, and water tree aging. Eventually the cable is broken down by insulation

[0004] In order to find the cable insulation status in time, it is necessary to use the cable insulation online detection device to monitor the cable in real time; the existing cable insulation detection methods mainly include: low-frequency voltage superposition method, high-frequency voltage superposition method, DC component method, cable dielectric loss method, DC Voltage superposition method, harmonic component method, etc. These methods have their own advantages, but there are also some problems. Therefore, in practice, the online detection method of cable insulation is still in the stage of continuous improvement.

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