What is meant by impulse voltage?

What is meant by impulse voltage?

[′im‚pəls ‚vōl·tij] (electricity) A unidirectional voltage that rapidly rises to a peak value and then drops to zero more or less rapidly. Also known as pulse voltage.

What is rated switching impulse withstand voltage?

The rated switching-impulse withstand voltage for a circuit breaker is the crest value of the standard switching-impulse voltage wave which a circuit breaker must be capable of withstanding without puncture or damage when tested under specified conditions.

Why is impulse voltage used?

The purpose of the impulse voltage test is to secure that the transformer insulation withstand the lightning overvoltage which may occur in service. When the charging voltage has reached the required value, breakdown of the spark gap F1 is initiated by an external triggering pulse.

What is meant by switching surges?

A switching surges is a short duration transient voltage produced in the system due to a sudden opening or closing of a switch or circuit breaker or due to an arcing at a fault in the system.

How impulse voltage is generated?

For the production of impulse voltages, a number of parallel-connected impulse capacitors is charged by means of the charging resistors. After the capacitors are charged to the desired energy, they are connected in series by means of spark gaps, and then discharged.

What is full wave impulse withstand voltage?

Full-Wave Withstand – the industry-accepted standard test- voltage wave shape for all types of insulation is 1.2 x 50 microseconds with a continued gradual decay to zero on the wave tail. Withstand Voltage-highest value of applied voltage at which equipment will not flashover.

How do you test a transformer for impulse?

Impulse testing of transformers is done using both the full wave and the chopped wave of the standard impulse, produced by a rod gap with a chopping time of 3 to 6 µs. To prevent large overvoltages being induced in the windings not under test, they are short circuited and connected to ground.

What is the purpose of impulse testing?

Impulse testing systems are designed to generate impulse voltages that simulate lightning strikes and switching surges. The complete test system consists of a charging rectifier, impulse stages according to the “Marx Circuit”, an impulse voltage divider and impulse voltage measurement system.

What is lightning and switching surges?

Switching Impulse or Switching Surge When a no load transmission line is suddenly switched on, the voltage on the line becomes twice of normal system voltage. This voltage is transient in nature. But over voltage surges appear in the system due to lightning impulses are very high in amplitude and highly destructive.

What are the switching over voltages?

Apart from being caused by dielectric faults or flashover, switching overvoltages appear in the power systems due to switching of load and/or fault currents, and they cannot be avoided. All network switching operations result in a certain level of transient overvoltages that propagate through the system.