Method and system for monitoring hidden faults of power supply equipment

Abstract

The present disclosure relates to a method and a system for monitoring hidden faults of grid power supply equipment. The method defines a virtual node including several power supply devices, calculates the true RMS electric energy flowing into the virtual node and the true RMS electric energy flowing out of the virtual node within 0.1s in real time with a period of 0.1s, and marks it with precise time scale. Then, the electrical energy losses occurring in the virtual nodes are continuously calculated over a time window of multiple cycle scales. Finally, through the virtual resistance method, the loss comparison method of similar virtual nodes, and the historical loss comparison method, it is judged whether there is a hidden fault in the internal equipment of the virtual node. The system based on this method includes a true effective value electric energy synchronous measuring device and a hidden fault monitoring station domain master station of power supply equipment, which is suitable for monitoring non-control circuit faults of power supply equipment.

Description

technical field [0001] The invention belongs to the technical field of power grid fault diagnosis, and in particular relates to a method and system for latent fault monitoring of power supply equipment. Background technique [0002] The power grid relies on a large number of lines, switches, transformers, capacitors, frequency converters and other power supply equipment to complete the transmission of electrical energy from power generation equipment to electrical equipment. These power supply devices themselves or their interconnected joints, contacts and insulation may often have poor contact, discharge or non-metallic short circuit problems, resulting in heat generation, which may eventually lead to fire or explosion, which seriously affects the safety of power transmission and power supply. This is especially common in low voltage supply systems of 400V or 6kV. For example, poor contact occurs at the drawer inlet of a 400V switch cabinet in a chemical enterprise, which ...

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Problems solved by technology

[0004] Existing fault monitoring methods for power supply equipment have various shortcomings that limit their wide application

For example, the ultrasonic monitoring method relies on external signals and is difficult to apply in real time. The traveling wave analysis method is not suitable for short lines or equipment. The electromagnetic coupling method for testing partial discharge needs to install a built-in partial discharge sensor, which is difficult to adopt in existing equipment. Wavelet analysis method and neural network method It is greatly affected by the type of fault point and interference type

Therefore, there is no perfect monitoring method for hidden faults of power supply equipment for a wide range of fault types.

[0005] In addition, it should be pointed out that temperature rise is also a common feature of power supply equipment failure, but the measurement sensitivity of temperature rise is much lower than the measurement of transmission power loss, which is not conducive to early detection of faults

In addition, the abnormal temperature can be detected in time only when the temperature sensor is installed near the fault point. However, the fault point is often difficult to predict, or there are too many sensors to install a large number of sensors.

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