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The waterproof bushing of oil-immersedtransformer is a commonly used spare part. Whether it is oil-transformed oil-immersed transformer or dry-test oil-immersed transformer, everyone sees this kind of component outside the oil-immersed transformer. Today, everyone will give a detailed introduction to the two key aspects of characteristics and efficacy, and do some expansion of the response: Regarding the waterproof casing, there are generally two types of capacitive sensors and non-capacitive types, and the rated current is not less than 35kV. Type waterproof casing The tube is generally all capacitive sensor waterproof casing. Why is it so divided? The main reason is that their materials are different, and the working voltage that can be carried is different.

Therefore, this extends to your detailed introduction to the efficacy of oil-immersed transformer waterproof bushings:

1. Efficacy

The waterproof casing often needs to bear the working voltage, because the winding must rely on the waterproof casing to be connected to the oil tank of the oil-immersed transformer. Therefore, if the waterproof casing is frequently faulty, the oil-immersed transformer will not work immediately. Common faults It may also be due to fire accidents, etc.

Let us interpret it in detail below: the fuel tank of the oil-transformed oil-immersed transformer is made of steel and has a grounding device. The ground wire of the wound transformer can only be connected to the power grid according to the oil tank; and the ground wire of the wound transformer must be connected to the oil tank with the help of a waterproof casing. The waterproof bushing is a part of the ground wire of the winding transformer and is a part of the winding circuit.

2. Detailed introduction of features:

Generally, the characteristics of the waterproof casing that oil-transformer oil-immersed transformer manufacturers are concerned about are the insulation performance and thermal characteristics. These two performances can determine the reliability of his work and ensure the extraordinary performance of his effects. The following Let me introduce these two small points:

A. Insulation performance A. Important characteristics of the inner insulating layer. The important insulation performance of the capacitive sensor waterproof casing can be specified: excellent sealing function, no water leakage; partial discharge level lower than 10pC; tan stable.

B. Important characteristics of the outer insulating layer. The outer insulating layer of the waterproof casing refers to the insulating layer of the outer layer of the waterproof casing and the air contact part, and the oil or SF. The outer layer that the vapor touches does not belong to the outer insulating layer. The important characteristic of the outer insulation of the porcelain sleeve is that the creepage distance of the waterproof sleeve is consistent with the pollution level of the application site, and there is a margin.

(2) Thermal characteristics

A. Thermal characteristics of current-carrying conductors. The thermal function of the current-carrying conductor is to specifically guide the poles, cables and terminal blocks whether it is possible to generate over-temperature when the long-term operating current is based on the rated value or the short-term operating current is based on the amount of overcurrent. The heating of the cable or the conductive rod is related to the selected current intensity, and no common faults have occurred when the rated current is applied. The temperature rise of the terminal block is related to various factors such as apparent current intensity, coating quality (including tin plating, gold plating, etc.), and tightening force. The common fault of over-temperature in the terminal block is generally not a structural problem caused by non-standard connection, but is actually caused by the actual operation during connection.

B. Thermal characteristics of the insulating layer of the waterproof casing core. The thermal characteristics test of the insulating layer of the waterproof casing core is called the heat resistance test by the national industry standard. During the test, the waterproof casing is infiltrated into the oil-immersed transformer oil at (90 ± 2) ℃, and the conditional relationship between the insulation layer of the waterproof casing core and the moisture content of the current-increasing elephant is accurately measured.

 

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S11-M-07


Post time: Jun-14-2022