How to deal with faults in 10kV switchgear-INNO

10kV switchgear structure

The 10kV switchgear used in the mine is generally composed of two main parts: circuit breakers and cabinets. The cabinets are physically divided into busbar room, control room, outgoing room, and circuit breaker room. Due to the harsh mining environment and heavy loads, there are higher requirements for the reliability of equipment operation. Its notable features are narrow space and compact structure.

Common faults of 10kV switchgear

Com o rápido desenvolvimento da ciência e da tecnologia, the quality and reliability of 10kV switchgear have been significantly improved, and the failure rate of equipment has been greatly reduced. No entanto, due to the large load in the mine and the harsh environment, as well as the 10kV switchgear working in high voltage and high current environments, é difícil evitar falhas no equipamento.

Entre as falhas comuns do quadro de distribuição de 10kV, aquecimento, isolamento, e falhas de componentes são responsáveis pelos três principais, contabilidade para 48.15%, 27.78%, e 11.11% respectivamente, totalizando 87.04%. A ocorrência dessas falhas tem sérios efeitos adversos na segurança do fornecimento de energia da mina, e medidas técnicas eficazes devem ser tomadas para prevenção e tratamento. Embora as falhas mecânicas e outras representem uma pequena proporção, a sua ocorrência tem um impacto muito adverso na produção normal da mina.

Análise das causas de falhas em quadros de 10kV

10Falha de aquecimento do painel kV

Durante a operação do quadro, as principais fontes de geração de calor vêm do circuito condutor, especificamente da posição comum, aquecimento do condutor, aquecimento por correntes parasitas, e outras peças. Se a geração de calor do equipamento for maior que a dissipação de calor do quadro, it will cause the temperature of the switchgear to increase, e em casos graves, it can cause malfunctions. Joint heating mainly occurs at knife switch joints, joint positions, transformer connecting plates, and other locations where there may be poor contact, or due to electrochemical corrosion, the equipment may have poor contact, resulting in sparks or heating. The main reason for conductor heating is the heating of the busbar in the busbar room. The busbar passes through a high current value for a long time. When the switchgear load is high, the heating of the busbar is more obvious. Due to the limitations of production technology and conditions, it is difficult to avoid impurities in the produced busbar, which increases the resistivity value and also increases the heat generation of the busbar. Eddy current heating is mainly caused by the circulating current of the load current due to the partition effect of the steel plate inside the switchgear, causando aquecimento. The larger the load current, the more severe the eddy current heating phenomenon.

Insulation fault of 10kV switchgear

Insulation discharge is the main factor causing insulation faults in switchgear, such as ground flashover, conductor phase to phase flashover, and pillar porcelain bottle flashover. When the insulation strength of the insulation or gap between the insulators inside the switchgear is insufficient to meet the insulation requirements, discharge may occur during operation in a high-voltage environment. Em casos graves, direct penetration of the insulation may occur, leading to insulation faults. The harsh operating environment of 10kV switchgear in mines is an important reason for insulation faults, with the most typical being the occurrence of pollution flashover. There is a large amount of dust in the mining environment, and due to the accumulation of time, there is a lot of pollution in the insulators, sleeves and other components inside the switchgear. When the air humidity is high and the insulator support is close to the leakage point, it is extremely easy to cause pollution flashover.

10kV switchgear component failure

There are many precision components inside the switchgear, which are prone to malfunctions under long-term high load operation. Entre eles, the probability of live displays malfunctioning is relatively high, and many 10kV switchgear live displays in mines are in a faulty state, which is virtually non-existent and cannot be used on site; The main reasons for the failure of voltage transformers are due to equipment installation and debugging, equipment quality, equipment overvoltage, and short circuits on the secondary side; The main causes of lightning arrester failure are seal failure, porcelain contamination, and aging of valve plates due to prolonged equipment operation. When the seal fails, it will cause moisture and dust from the external environment to enter the interior of the lightning arrester, causing insulation degradation and accelerating the aging process of the valve plate. Ao mesmo tempo, when the porcelain sleeve is contaminated, it will cause uneven voltage distribution inside the resistor plate and intensify the aging of the resistor plate.

Mechanical failure of 10kV switchgear

The most common mechanical faults that occur in switchgear include broken pull rods, bent or deformed operating components (or localized fractures), broken transmission pins, and broken pull rods. These mechanical faults can cause the connecting rods to fall off, resulting in short circuits in the internal circuits of the switchgear and single-phase grounding accidents. Em casos graves, it can lead to insensitive operation of the entire switchgear, and even the inability to close or open the switch. In addition to the above faults, the main reasons for other faults in the switchgear are operator and maintenance personnel’s misoperation, or snakes, mice, etc.. entering the switchgear, causing equipment short circuits.

Common troubleshooting measures for 10kV switchgear

Carry out equipment installation and debugging work well

When the 10kV switchgear is transported to the mine surface substation, installation and debugging work should be strengthened to lay the foundation for the continuous and stable operation of the equipment in the future. The complete debugging of the switchgear is an important means of preliminary troubleshooting of equipment faults. When debugging the switchgear, it is necessary to eliminate whether the insulation gap inside the equipment meets the requirements, whether there is jamming in the transmission, and other situations that do not meet the requirements, in order to create good conditions for future equipment operation. When equipment malfunctions are found during the installation and debugging process, the installation and debugging personnel should immediately report to the mine management personnel and communicate with the equipment manufacturer for handling.

Improve the insulation performance of switchgear

Due to the harsh environment in which the mine is located, high equipment workload, and the need to work for a long time in a high-voltage environment, higher requirements are placed on the insulation performance of the switchgear. Mining 10kV switchgear should pay attention to the insulation performance of the equipment in the early stage of material selection. High standard and high-quality materials can make the switchgear work better and reduce the probability of insulation failure of the equipment. When selecting a switchgear, the first thing to choose is to use an organic insulation material with better insulation performance. Ao mesmo tempo, the components used inside the switchgear should have better insulation performance, and there should be a flame retardant partition in the middle. The voltage transformer should pay special attention to its volt ampere characteristics. For switchgear that has been in service for a long time, attention should be paid to equipment cleaning to minimize the possibility of switchgear failure caused by dust.

Seal the switchgear properly

The sealing performance of switchgear is closely related to its safe operation, and good sealing is an important condition to ensure the safe and efficient operation of switchgear. Primeiramente, the protection level of the internal partitions of the switchgear should be strengthened. A estrutura interna do quadro inclui principalmente disjuntores, barramentos, e cabos. Esses componentes são divididos em pequenos compartimentos usando divisórias de isolamento retardantes de chama. Se um compartimento não funcionar corretamente, não causará mau funcionamento dos compartimentos adjacentes, evitando que a falha se expanda. Os plugues utilizados dentro do equipamento devem ser cobertos com isolamento para proteger a segurança dos operadores e do pessoal de manutenção.

Em termos de operação mecânica do quadro, é necessário observar rigorosamente os regulamentos e substituí-lo em tempo hábil quando forem encontrados problemas.

Fortalecer a manutenção regular e o gerenciamento dos quadros de distribuição com base na situação real da mina. Com base no modelo específico e na vida útil do equipamento, a reasonable equipment maintenance and repair plan should be formulated. In the specific implementation process, targeted maintenance and repair should be carried out according to the actual situation of the equipment, while following the rules and regulations. When maintaining the equipment, pay attention to observing whether the switchgear has any odor, cor, som, vibração, or other abnormalities. After discovering the above issues, it is necessary to conduct a comprehensive investigation of the switchgear.

Strengthen the inspection of the switchgear and timely grasp the operating status of the switchgear. During the inspection process of the switchgear, be careful and meticulous. Às vezes, a small discharge inside the switchgear may turn into an insulation accident during the next inspection. Ao mesmo tempo, infrared equipment is used to detect the conductive lines and connections inside the switchgear that are prone to temperature abnormalities. Once abnormalities are detected, the working load of the switchgear should be appropriately reduced to avoid further temperature rise and cause faults.

Develop preventive measures

For the malfunction of 10kV switchgear caused by misoperation, por um lado, the mine should establish reliable and complete rules and regulations, and strictly implement them. Por outro lado, it should strengthen the training of switchgear maintenance and repair personnel, improve their professional skills, and prevent misoperation. During the daily inspection of the switchgear, any problems found should be promptly reported and dealt with.

10kV switchgear is widely used in mines, and due to the harsh mining environment, the switchgear operates at high loads for a long time. The problems and types of faults that occur during operation are also diverse. Portanto, the author has conducted a statistical analysis of common faults in switch cabinets in mines in recent years, summarized the common types of faults, and proposed targeted measures from the installation and debugging of switch cabinets, improving insulation performance of switch cabinets, doing well in switch cabinet sealing, strengthening regular maintenance and management of switch cabinets, and formulating preventive measures to reduce the possibility of faults in 10kV switch cabinets and improve mine power supply safety.