High-voltage switchgear is a very important electrical equipment in the power system. The deterioration of the operating state of the switchgear is one of the causes of power system failure. So, what are the common faults of high-voltage switchgear?
(1) Outdoor and indoor
From the placement of high-voltage switchgear, it can be divided into outdoor type and indoor type, and 10KV and below adopt user type. According to the different schemes of the primary line, it can be divided into inlet and outlet switchgear, contact oil switchgear, busbar segmentation cabinet, etc. 10KV inlet and outlet switchgear is installed with less oil circuit breaker or vacuum circuit breaker, circuit breaker equipped with operating mechanism is mostly spring operating mechanism or electromagnetic operating mechanism, but also equipped with manual operating mechanism or permanent magnet operating mechanism. Different switchgear have great differences in structure, which will affect the selection and installation of sensors.
(2) Fixed type and removable type
From the use of high-voltage switchgear, it can be divided into fixed type and removable type. In the past, the power supply system of the power plant used to use removable switchgear, while the power supply system used more fixed cabinets. With the advancement of science and technology and the continuous development of new products, many idioms are also changing. For example, the metal armored removable switchgear was developed on the basis of the fixed switchgear. The metal armored removable switchgear is a fully enclosed structure, and the functional chambers are separated from each other, the normal operation performance and anti-misoperation function are perfect and reasonable, the maintenance is convenient, and the safety and reliability of its operation are greatly improved.
(3) The development of high-voltage switchgear
In recent years, with the development and promotion of small vacuum circuit breaker technology, the new development of mid-mounted switchgear as a metal-enclosed armored removable switchgear has been developed rapidly. There are many advantages of the central cabinet, the most important is the miniaturization of the handcart and the mechanization of the production process, so that the production of the handcart and guide rail is more accurate. There are even many manufacturers' products, their handcarts including the main circuit breaker and cabinet do not have to be one-to-one debugging in the factory, and it is easy to debug successfully after they are shipped to the site when they leave the factory, which can also ensure that the handcart is flexible and convenient. Due to the good interchangeability of the product, it is very little affected by the horizontal conditions of the ground on site. This metal armored removable switchgear is safe and reliable in operation and easy to maintain and maintain. Therefore, more and more power supply systems are used.
Second, the analysis of common faults of high-voltage switchgear
Analyze the causes of high-voltage switchgear failures, mostly in insulation, conductivity and machinery.
(1) Failure to move or misuse
This fault is the most important fault of the high-voltage switchgear, and its causes can be divided into two categories. One type is caused by the mechanical failure of the operating mechanism and transmission system, which is specifically manifested as mechanism jamming, component deformation, displacement or damage, loose and astringent core of the closing gate, loose shaft pin, trip failure, etc. The other category is caused by electrical control and auxiliary circuits, manifested as poor secondary wiring contact, loose terminals, incorrect wiring, burning of the split and closing coil due to mechanism jamming or poor transfer switching, poor switching of auxiliary switches, and failure to operate the power supply, closing contactor, micro switch and so on. WeChat technology training deserves your attention.
(2) Breaking and closing failures
This kind of fault is caused by the circuit breaker body, and for the low-oil circuit breaker, it is mainly manifested as short circuit of fuel injection, burned arc extinguishing chamber, insufficient breaking capacity, explosion during closing, etc. For vacuum circuit breakers, the manifestations are air leakage of the interrupting chamber and bellows, vacuum degree reduction, re-ignition of the cut capacitor pack, and rupture of ceramic tubes.
(3) Insulation failure
The insulation level is to correctly deal with the relationship between various voltages (including operating voltages and various overvoltages), various voltage limiting measures, and dielectric strength acting on the insulation. Strive to make the product both safe and economical, and get the best economic benefits. The faults in insulation are mainly manifested as external insulation to ground flashover breakdown, inner insulation flashover to ground flashover, interphase insulation flashover breakdown, lightning overvoltage flashover breakdown, porcelain bottle sleeve, capacitor sleeve flashover, pollution flashover, breakdown, explosion, lifting rod flashover, CT flashover, breakdown, explosion, porcelain bottle breakage, etc.
(4) Current carrying fault
The current carrying fault of the 72~12KV voltage level is mainly caused by the poor contact of the switchgear isolation plug, resulting in contact melting.
(5) External forces and other failures
Including foreign body impact, natural disasters, small animal short circuit and other unknowable external forces and unexpected failures.
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