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What is the solution and treatment method for overvoltage of VS1 vacuum circuit breaker?

2023-11-16


In the previous article, we talked about the generation and harm of over voltage of VS1 vacuum circuit breaker? In this article, we will solve the problem of over voltage and how to deal with it?

What specific methods do we have to prevent the occurrence of over voltage in the VS1 vacuum breaker?

1. Inductance protection of vs1 vacuum circuit breaker:

An LR over voltage suppressor is formed by connecting a reactance coil (or saturable reactor) and a resistor in parallel between the vs1 vacuum circuit breaker and the motor power supply cable to suppress the rising steepness and peak value of the over voltage.

2. Capacitor protection of vs1 vacuum circuit breaker:

Connecting a capacitor in parallel at the inductive load end can effectively reduce the load impedance, thereby reducing the amplitude of the interception over voltage, and also slowing down the steepness of the leading edge of the over voltage. This not only protects the inductive load from damage by the interception over voltage, but also It can reduce the harm to motor insulation caused by multiple reignition over voltages. The vs1 vacuum circuit breaker is connected to the transformer or motor with a cable. Since the cable has a large distributed capacitance, its function is equivalent to a parallel capacitor, and the effect is very good.

3. Resistor-capacitance protection of vs1 vacuum circuit breaker:

The resistor R and capacitor C are connected in series as a protection element and connected in parallel at the load input end to form an RC over voltage suppressor. The capacitor can not only slow down the rise steepness of the over voltage, but also reduce the wave impedance of the load, thereby reducing the interception over voltage. The function of the resistor is: when current cut-off occurs, its presence increases the attenuation coefficient of the high-frequency discharge circuit, which can reduce the number of re-ignitions and multiple re-ignition over voltages, and can even effectively prevent its occurrence. Using an RC suppressor to protect loads such as motors has the best effect.

4. Non-linear resistance protection of vs1 vacuum circuit breaker:

(1) Use an ordinary lightning arrester in parallel with a capacitor. The ordinary arrester can limit the amplitude of over voltage, and use a capacitor to slow down the steepness of the over voltage rise. (2) Metal oxide arrester is used, which uses ZnO varistor. It is an arrester without arc extinguishing gap and has the stable characteristics of semiconductor transistors. Under normal operating voltage, the resistance is very large and the current is very small. When the voltage increases to a certain value, the resistance decreases and shows stable characteristics. It should be noted that when using a metal oxide arrester for over voltage protection, its model must be consistent with the system voltage, and the capacity of the inductive load or capacitor bank should be appropriately matched.

The above method of dealing with over voltage.