This combination of size and power makes very low frequency cable testing perfect for testing longer sections of cable and apparatus.
Vlf cable testing procedure pdf.
It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs.
Reduction in cable life.
During the test cables are subjected to a test voltage significantly higher than what they experience during normal operating conditions.
The benefits of vlf maintenance testing regular routine maintenance testing of aged cables has been demonstrated to reduce the chance of unscheduled failure to approximately 10 of the failure rate that might be encountered without such testing.
Overview this guide provides a description of the methods and practices to be used in the application of very low frequency vlf high voltage excitation for field testing of shielded power cable systems bach b1 1 and 2 2.
There are no rules of thumb to be used.
Vlf testers are smaller and more practical than ac testers but output the same amount of power as a 50 hz mains device.
Vlf cable test voltages and time durations are set by ieee standard 400 2 2013.
Ieee 400 4 2015.
Ieee guide for field testing of shielded power cable systems using very low frequency vlf 1.
Ieee guide for field testing of shielded power cable systems using very low frequency vlf less than 1 hz.
The cable tests described below are to be carried out after.
Thus it is quite natural for utilities to also use withstand and partial discharge tests as commissioning and maintenance tests for cable.
Very low frequency vlf withstand testing is the application of an ac sinusoidal waveform generally at 0 01 0 1 hz to assess the quality of electrical insulation in high capacitive loads such as cables.
These numbers result from many years of vlf field use and research.
The test measures the insu lation resistance between the phases and or between phase and ground.
Ieee 400 3 2006 ieee guide for partial discharge testing of shielded power cable systems in a field environment.
Approximately 12 of cables fail during the test and cable repair can then be done in a planned manner.
Vlf testing uses very low frequencies as part of an ac cable maintenance routine.
Vlf tan delta and withstand testing of electrical power cables 6 maintenance test a field test made during the operating life of a cable system.
Insulation resistance testing purpose.
It is intended to detect deterioration of the system and to check the serviceability so that suitable maintenance procedures can be initiated.
High voltage withstand tests are used in conjunction with partial discharge measurements on solid dielectric cable and accessories within manufacturing plants to ensure the quality of completed cable system components from mv to ehv.
