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Uninterruptible insulation test method and leakage detection service principle method V6808 tester oem

The importance of leakage detection and the principle and method of detection

The occurrence of leakage is due to the fact that the insulation ability of the wire or the insulation capacity of the bracket material decreases due to some reason (natural or man-made reasons, such as wind blowing, humidity, high temperature, pressure, scratching, friction, corrosion, small animal damage, etc.) in a certain place of the line, resulting in a part of the current passing between the wire and the wire (through the damaged insulation, bracket, etc.), between the wire and the earth (the wire passes through the steel bar, tinplate sheet, etc. of the cement wall), and this phenomenon is leakage. When leakage occurs, the leakage current will be on the way to the earth, if it encounters a part with large resistance, it will produce local high temperature, causing nearby combustibles to catch fire, thus causing a fire. In addition, a leakage spark generated at the point of leakage can also cause a fire.   

Principle of leakage detection

As shown in Figure 1, if the current flowing through the wire is I, I will generate an electromagnetic field around it, and the strength of the electromagnetic field is proportional to the magnitude of the current in the wire. The current transformer (or high-precision flexible coil clamp meter V6808) is a high permeability device, which is placed in the electromagnetic field, and the alternating current (i.e., leakage current) I1 residual current transformer (or high-precision flexible coil clamp meter) will be induced in the secondary coil V6808) is the basic module for residual current monitoring, when passing through the L, N (three phases are A, B, C , N), as shown in Figure 2, an induced current signal is generated on the secondary coil side of the transformer, and the actual residual current value (Note: Due to the limited space between some cables or the end of the ABCN of the cable can pass through the flexible coil clamp at the same time or close to the live part too close to the live part and other safety factors, all cables can be tested for leakage, and the distribution system where the ground wire and the neutral wire are connected together is not applicable).Based on the residual current value, it is possible to determine whether the insulation of electrical equipment is good.

Leakage current detection is based on GB50116

According to the relevant requirements, the point where the on-site leakage exceeds 500mA (0.5 A/a) needs to be investigated.

1)The insulation between the line and the ground drops to a dangerous value due to moisture or water ingress into the electrical equipment in operation;

2)During the installation and operation of the cable, cracks or cracks are caused by mechanical or other external forces, such as squeezing, chopping, excessive bending, etc., and the insulation is damaged by moisture corrosion for a long time; or small animals destroy the cable sheath, etc.;

3)The cable is not firmly connected with the equipment, the pl ing is not tight, and the terminal pressure plate is not tight, which causes the connector to fall off during operation or movement, or the joint is loose, so that the wire is lapped with the metal shell, or the insulation is damaged when the joint is overheated, resulting in leakage;

4)When repairing electrical equipment, due to careless work, tools, materials and other conductive materials are left inside, resulting in leakage;

5)When operating electrical equipment, leakage occurs due to the short connection between the wire and the ground caused by arc discharge; Long-term overload operation of electrical equipment or cables can cause damage to the aging of the insulation