Apparatus for detecting contact corona and arc-drawing of high voltage switch cabinet

Abstract

The invention discloses a contact corona and arc detecting device of a high voltage switchgear, which comprises a detecting unit, a data analysis and processing unit, a displaying unit, a network communication unit and a power supply unit, wherein the detecting unit adopts a sensor to output switchgear contact and arc signals to the data analysis and processing unit, one part of input signals is output to the displaying unit to display the detecting results after the data analysis and processing unit analyzes and processes input signals, and the other part is output to the network communication unit, and the detecting data are sent to a host computer through networks, and the power supply unit is electrified by devices. The contact corona and arc detecting device solves the problem on howto detect contact and arc of a high voltage switchgear, has the function of remote monitor and control, can reliably and accurately send out alarming information in time, and can be widely used on on-line monitoring contact and arc of high-voltage switch apparatuses of various electric force.

Description

technical field [0001] The invention belongs to the field of electric power safety operation detection, and in particular relates to a high-voltage switch cabinet contact corona and arc detection device. Background technique [0002] With the development of the power grid and the improvement of equipment technology, 10kV and 35kV system switchgears have been widely used in the power grid. The internal overheating of the switchgear has become a common problem in the use of the switchgear. Before the overheating, there are often high-voltage corona flashovers or switch arcing in the switchgear. Arc discharge is a form of gas discharge. Its discharge mechanism is that the conductive ions between the electrodes are continuously generated and disappeared, and it is in a state of dynamic balance. Its condition is that the power supply has enough energy to continuously input the discharge point. In the discharge gap form discharge channels. Because in the initial stage of arc dis...

AI Technical Summary

Problems solved by technology

During operation, under the action of the electromagnetic vibration force caused by the large load current, the screws of the contact part are loosened, causing a gap to form on the surface of the dynamic and static contact or joint, resulting in spark discharge in the gap. Although the energy is not large, the temperature can reach hundreds of degrees Celsius or even thousands of degrees Celsius. degree, resulting in the formation of serious electric corrosion pits on the surface of the contact, thereby reducing the effective contact area, resulting in a further increase in contact resistance and severe heating

Arcing is caused by poor contact contact and melting, resulting in a short circuit between phases of the busbar, which can quickly develop into a three-phase short circuit or internal failure of the high voltage transformer, explosion damage

[0004] 2. If the interior of the arrester is damp, it may cause a flashover on the inner wall of the arrester and cause the arrester to explode, and then cause an arc short circuit of the grounding switch, that is, an arc explosion

[0005] 3. The high-voltage transformer damage accident caused by the heating and arcing of the working power switch

[0006] 4. For switch cabinets with live parts such as busbars, switch isolation plugs, or the air distance to the ground is not enough, corona discharge is more likely to occur under the conditions of high operating temperature, high humidity, and impurities in the air. In the worst case, it can also cause air gap breakdown to form a short circuit

[0007] 5. Overvoltage occurs in the contacts of the switch cabinet, resulting in poor breaking performance of the switch and causing arcing

There are burrs on the busbars and components in the cabinet, which cause tip corona discharge, which leads to uneven electric field distribution on the insulating surface. When the local electric field strength reaches its critical field strength, the gas is partially ionized and blue fluorescence occurs. The thermal effect and Ozone and nitrogen oxides will damage the insulation of the insulator

[0009] 7. Thermal breakdown and pollution flashover

In the handcart cabinet, a large number of insulating parts made of die-casting epoxy resin are used, especially the outer insulating layer of high-voltage cables made of composite insulating materials, epoxy cast current transformers, phenolic epoxy insulating covers, interphase partitions and brackets. Under the action of the AC electric field and the temperature rise effect of the contact part, dielectric loss will be generated, resulting in an increase in the temperature of the medium, and the increase in temperature will further increase the dielectric loss

If the heat dissipation conditions of the cabinet are poor, the heat generated by the medium exceeds the heat dissipated, which will inevitably form a heat accumulation effect, and the high temperature will cause the medium to melt, burst or burn and completely lose its insulation performance, resulting in thermal breakdown.

At the same time, compared with porcelain insulation, composite insulation materials have poor water repellency. If the insulation material is not made of When damp, dirty or damaged, due to the increase of free electrons on the surface of the wet action medium, the conduction current also increases, so the insulation resistance decreases accordingly. When the insulation drops to a certain level, it will cause local discharge flashover along the surface, and eventually develop Phase-to-phase short circuit or ground short circuit accident

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