Different Short - circuit of Load Switch

With the successful development of the electric switch mechanism dedicated to the load switch, the load switch to achieve a long-range control of the sub-operation, which for the external type of energy meter load control switch to bring new opportunities for development. Most of the external cost control load switch, the use of small circuit breaker structure type, due to increased pre-paid function, making the product function is not only a simple over-current protection, need to have controllable homogeneous operation performance. 

 Therefore, the power system on the cost control load switch the reliability of the higher requirements, not only to successfully complete the line overload, short circuit protection, and requires its short circuit protection and troubleshooting points, the product performance can continue to To ensure the normal power supply circuit. Installed in the line of the load break switch, due to the power system in the transformer capacity, transmission line impedance, the user side and the transformer distance, the load side of the line is very different, resulting in short circuit flows through the load switch fault current size varies. Based on the load switch is generally installed in the terminal of the line, the actual short circuit current of the majority of 630 ~ 6 000A, therefore, by a group of the same specifications of the type of load switch (small circuit breaker) in different short-circuit test current test analysis, Help to study the actual situation of products in different circuits, help to study the product failure reasons and key functional components.

How to choose the right load switch

load break switch is mainly used to break and close the load current, can also be used in conjunction with high-voltage switch with the high-voltage fuse, instead of circuit breakers. As the load switch is easy to use, the price is reasonable, so the load switch in the 10kV distribution system has been widely used. In the design of a reasonable choice of load switch, to protect the safe and reliable operation of the power grid is of great significance. 
Load switch and the correct combination of the fuse The difference between the load switch and the fuse is that the fuse has a short circuit current capacity, and the load switch only as a load current switching. It is generally believed that the load switch divides the operating current and the fuse is breaking the short-circuit current.
But when the failure occurs, because the three-phase current is not necessarily the same, and the fuse promised error, inevitably there is a three-phase fuse between the fuse time difference, the Prime Minister cut off the fault, if the load switch can not break the load current, Resulting in a transfer current and two-phase operation, causing damage to the power receiving equipment.

Fuse with impactor, with a trip device with a load switch, you can solve the problem of missing phase operation. When the fuse of the fuse melts, load switch tripping device is disconnected immediately after the striker operation. Production plant more use of four-bar linkage, when the load switch closing operation, the sub-gate spring at the same time energy storage, when the four-link mechanism dead point, closing the spring energy release, switch for closing operation, this time The energy of the gate spring is still maintained by the axle mechanism, once the impactor attack, axle out of the column, the sub-gate spring energy release, switch for sub-gate operation. Therefore, in use must be selected with a striker fuse and a mechanical trip device with the load switch.