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a. Install all cooling devices as specified by the manufacturer;

b. The cooling system with strong oil circulation must have two independent power sources and can be switched automatically. When the working power supply fails, it should be automatically put into the standby power supply and send out sound and light signals;

c. Strong oil circulation transformer, when cutting the fault cooler should send sound and light signals, and automatically (water cooling can be manually) into the standby cooler;

d. The attached motor of fan, water pump and oil pump should be protected from overload, short circuit and phase break; There should be a device to monitor the rotation direction of the oil pump motor;

e. The oil pump of the water cooler shall be installed on the oil inlet side of the cooler, and ensure that the oil pressure in the cooler is about 0.05MPa greater than the water pressure in any case (except otherwise specified by the manufacturer). The outlet side of the cooler should have a drain cock;

f. Transformer with strong oil circulating water cooling, check valve should be installed at the outlet of submersible oil pump of each cooler;

g. The transformer with strong oil circulation cooling shall be able to control the switching of the cooler according to temperature and/or load.

In normal operation of a power transformer, the core must be somewhat reliably grounded. If there is no grounding, the suspension voltage of the core to the ground will cause intermittent breakdown and discharge of the core to the ground. After the core is grounded at one point, the possibility of forming the suspension potential of the core is eliminated. However, when the core is grounded at more than two points, the uneven potential between the cores will form a circulation between the ground points, and cause the fault of multi-point grounding heating of the core. The core grounding fault of the transformer will cause local overheating of the core. In serious cases, local temperature rise of the core will increase, light gas action will even cause heavy gas action and tripping accident. The short circuit fault between the local core pieces of molten iron increases the iron loss, seriously affects the performance and normal work of the transformer, so that it is not allowed to replace the core silicon steel sheet for repair. Relevant data statistics show that the proportion of faults caused by core problems is the third of all kinds of transformer faults.

1. What is a transformer?

In AC circuit, the voltage will be increased or decreased equipment called transformer, transformer can be any value of voltage into the frequency of the same voltage value we need to meet the transmission of electric energy, distribution and use requirements. For example, the voltage level of the electricity emitted from the power plant is low, so the voltage must be increased before it can be transmitted to the distant power area, and the power area must be reduced to the appropriate voltage level to supply the power equipment and daily use of electricity equipment.

2. How does the transformer transform the voltage?

Transformers are made according to electromagnetic induction.

It consists of an iron core made of sheets of silicon steel (or silicon steel) and two coils wound around the core. The core and coils are insulated from each other and have no electrical contact with each other.

1. High frequency: Ferrite core

Ferrite core is used in high-frequency transformers. It is a ceramic magnet with a crystalline structure of spinel, which is iron oxide and other bivalent metallic compounds. Such as kFe2O4(k represents other metals), currently commonly used metals are manganese (Mn), zinc (Zn), nickel (Ni), magnesium (Ng), copper (Cu). Its common combinations such as manganese zinc (Mn Zn) series, nickel zinc (Ni Zn) series and magnesium zinc (Mg Zn) series. This material has high permeability and impedance physical properties, its use frequency range from 1kHz to more than 200kHz.

2. Low frequency: LAMINATION

Silicon steel sheet is used for low frequency transformer, there are many kinds, according to its different production process can be divided into A: forging (black), N: no forging (white) two kinds. According to its shape can be divided into: EI type, UI type, C type, mouth type.

3.COIL: There are three types.

The actual transformer core works in AC state, and the power loss is not only in the resistance of the coil, but also in the core under alternating current magnetization. The power loss in the iron core is usually called "iron loss". The iron loss is caused by two reasons, one is "hysteresis loss" and the other is "eddy current loss". Hysteresis loss is the iron loss caused by the existence of hysteresis phenomenon in the process of magnetization of the iron core.