Hipot

The high voltage test is used in the field of electrical engineering to ensure the insulation resistance of electrical equipment and electrical installations. It provides in this application is a part of the insulation measurement, which is performed with high voltage and requires special safety precautions.

The field of high voltage tests shall include procedures by means of impulse voltage generators for fault location on high voltage cables which are laid in the ground.

Testing of low voltage components

In the low voltage range used appliances with protection class I and II will be reviewed so that the insulation has a prescribed according to standard dielectric strength. It will also determine whether the insulation of the current carrying conductor and the safety distance from the housing in order. In principle, these high-voltage test is performed on the same connection points as the insulation resistance test. The test is performed with higher test voltages than the operating stresses occurring in normal operation. The test voltage may be either an AC and a DC voltage and is typically in the range of a few kilovolts.

When tested with both of the AC current through the ohmic insulation resistance, as well as by the capacitive insulation resistance can be detected. It is determined a total current of resistive and capacitive component. The actual insulation measurement also includes more extensive tests and measurements, which are not executed with high voltage.

Tests of high-voltage components

High voltage components that are used in the electrical industry and also be operated in normal operation with high voltage, such as circuit breakers, power transformers or insulators are tested under a high voltage test prior to final installation and final in Hochspannungsprüffeldern and partly in high voltage laboratory at the guaranteed limits.

This test voltages are used to in the range of 1 MV and just above it, which can be to determine the limits also on the permissible operating voltages. The benefits are much smaller than the nominal powers normally to avoid damage to the specimen. As a high-voltage source used special test transformers in combination with voltage multipliers such as the high voltage cascade to generate high DC voltages. To generate a high AC voltage test transformers several can be connected in series as a cascade. More high-voltage sources for testing represent the series resonant systems that find application in mobile testing equipment application. Marx generators are used to generate high, defined pulse voltages in the examination.

The high voltage test takes place in a closed-off area, which is also referred to as test field or high voltage laboratory. The area, such as a hall or a part of it, must, for safety during high voltage test not be entered and separated by electrically conductive walls or lattice of the adjacent control and control rooms. The additions in the high voltage test shall be secured on opening switches on the doors. For larger parts of the system, the barrier is ensured in parts of the factory building also by deployable barriers and conductive fences or walls, warning lights, beeps and signs.

In high- voltage tests special attention to avoiding the " carry-over " of the high-voltage measurement cables in areas outside the high voltage range is respected, because so may cause damage to instruments and control devices. To this end, all lines leading into or out of the high-voltage area, must be grounded on shields and overvoltage protection devices.

After the high voltage test and switching off the test equipment to prevent accidents are strictly regulated procedures, there is a danger of electrical accidents of charged parts of the plant such as high voltage capacitors after shutdown. Among the behaviors such as the five safety rules include, for example, that after the shutdown with grounding rods permanently visible links must be established before starting to work on the plant components on.