cause of the power capacitor explosion

In low voltage power system, the use of electric power capacitor is to improve the power factor of system, reducing reactive power loss.Power capacitor _ the damage happened in explosion accidents occurred frequently, even light distribution equipment damage, or destruction of buildings and cause fire.

A single power capacitor is made up of three capacitors connected into delta form, in the transformer oil seal container, the top lead to three terminals, as shown in figure l.Figure C is composed of a set of capacitor (two, three or more) and pick up.

Set A, B and A capacitor is punctured (see figure 2).Figure 2 is A, B and the equivalent circuit.Its equivalent resistance R for the plastic capacitor.Due to the breakdown is a gradual process of capacitor, the equivalent resistance R is a dynamic variable resistor.Breakdown process, the capacitor capacitance can produce joule heat, the joule heat expression for Q = I2Rt = U (AB) square/Rt = 380 square/Rt (J).Welcome to reprint, this article from the electronic enthusiasts net (..........com).

Because of the dynamic resistance R is from large to small, the longer, the more heat.When capacitors have excessive leakage current or breakdown, capacitor in a short time to produce a lot of heat energy, the heat energy in the capacitor oil decomposition to produce a large amount of gas, the capacitor shell cannot afford the sharp increase of pressure, casing damage and even explode.This is the main reason.

Secondly, as power factor compensation capacitor, the capacitor for refund amount related to the system.If frequent operation, call the voltage depression is just the reverse of residual charge polarity capacitor group, will produce a large current, the failure reasons of the capacitor.

                                                                                                                               Dingfeng capacitor --  cause of the power capacitor explosion