What are the classifications of distribution transformers? How to analyze the failure of distribution transformers? I believe these are not very clear to many people. After all, everyone only hears more in life, and there are too few contacts. If you want to know these, let's take a look at it with Xiaobian, let Xiaobian tell you what the distribution transformers are and how to analyze the distribution transformer faults for your reference.
Distribution transformer classification:
1. Classified by cooling method: dry (self-cooling) transformer, oil immersed (self-cooling) transformer, fluoride (evaporative cooling) transformer.
2, according to the way of moisture classification: open transformers, potted transformers, sealed transformers.
3, according to iron core or coil structure classification: core transformer (insert core, C core, ferrite core), shell transformer (insert core, C core, ferrite core) ), toroidal transformers, metal foil transformers.
4. Classified by power phase number: single-phase transformer, three-phase transformer, multi-phase transformer.
5. Classification by use: Power Transformer, voltage regulating transformer, audio transformer, intermediate frequency transformer, high frequency transformer, pulse transformer.
Distribution transformer failure analysis:
1. Three-phase load imbalance or seasonal overload
The three-phase load imbalance of the distribution transformer is a large number of existence from the survey results. In rural areas, most of the electrical load is single-phase load, and the load changes greatly. Therefore, there are many three-phase load imbalance of the distribution transformer, so that The three phases cannot operate symmetrically, producing a zero sequence current. This aspect increases the loss of the transformer and on the other hand reduces the effective capacity of the transformer. The above two conditions will cause the transformer to overheat and the insulating oil to age, which will reduce the insulation level of the winding and eventually cause the transformer to be damaged. The following measures can be taken: 1 Investigate the load of the distribution transformer, including the load of 24 hours a day and the load of 4 seasons a year, to clarify the general situation of the load, and adjust the three-phase load as close as possible to make it operate symmetrically. 2 Adjust the peak-to-valley time of the electricity to reduce the overload; at the same time, increase the capacity of the transformer in time to avoid long-term overload operation of the transformer.
2, poor grounding
The lightning protection work of the lightning-damage distribution transformer is generally done, but there are still two problems: 1 the lightning arrester is poorly grounded; 2 only pay attention to the high-voltage side installed lightning arrester, and neglecting the low-voltage side also needs to install the lightning arrester (especially Doree area). If the arrester is poorly grounded, when the overvoltage occurs, the arrester can not discharge the current well, which will damage the insulation of the transformer. If the arrester is not installed on the low voltage side, when the high voltage side arrester discharges a large lightning current to the ground, A voltage drop is generated at the grounding position, which acts on the neutral point of the low-voltage side winding while passing through the transformer casing, while the low-voltage side winding is grounded through the wave impedance of the low-voltage line. The following measures can be taken: 1 Check the grounding faults related to the arrester and re-adjust as required. Note Connect the grounding wire of the arrester directly to the outer casing of the transformer and the neutral point of the low voltage side, and then share the grounding device. The grounding resistance does not exceed 4 Ω. 2 For the multi-mine area, a low-voltage arrester should be added to the low-voltage side.
3, oil leakage oil leakage
There are also many leakages of transformer oil in distribution transformers. Due to leakage, the amount of oil in the transformer is reduced, the oil level is lowered, and the infiltration of air and water vapor is caused, the oxidation of the oil is accelerated to deteriorate, the viscosity of the oil is increased, the convection speed is lowered, and the heat dissipation of the transformer is affected. The higher temperature rise, which further accelerates the deterioration of the oil. At the same time, the acidity of the oil after deterioration is increased, which leads to a decrease in the insulation resistance of the winding, and even a damage to the insulation. In the long run, the transformer is inevitably damaged. The following measures can be taken: 1 Check the location of the oil leakage and handle it; 2 Check whether the transformer oil deteriorates and analyze the oil. If the transformer oil gradually turns from orange to brown, brown, and the viscosity of the oil is large, the transformer oil has deteriorated and must be cleaned or replaced. 3 When the transformer oil has not deteriorated, check whether the oil level is Too low. If it is too low, refuel to the mark on the transformer oil conservator; 4 check the insulation resistance of the winding.
The above is the introduction of the relevant content of the distribution transformer classification and how to analyze the distribution transformer failure. I believe that after reading, there should be some understanding of what is the classification of distribution transformers and how to analyze the failure of distribution transformers. I hope that everyone's understanding of this will help in the future.
