Vlf Cable Testing Procedure Pdf

Thus it is quite natural for utilities to also use withstand and partial discharge tests as commissioning and maintenance tests for cable.

Vlf cable testing procedure pdf. Ieee 400 4 2015. Ieee 400 3 2006 ieee guide for partial discharge testing of shielded power cable systems in a field environment. These numbers result from many years of vlf field use and research. 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.

Reduction in cable life. The test measures the insu lation resistance between the phases and or between phase and ground. It is intended to detect deterioration of the system and to check the serviceability so that suitable maintenance procedures can be initiated. Ieee guide for field testing of shielded power cable systems using very low frequency vlf 1.

Approximately 12 of cables fail during the test and cable repair can then be done in a planned manner. This combination of size and power makes very low frequency cable testing perfect for testing longer sections of cable and apparatus. 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.

Insulation resistance testing purpose. During the test cables are subjected to a test voltage significantly higher than what they experience during normal operating conditions. Dc high voltage testing of new xlpe cables is not recognised to cause cable deterioration however in order to adopt a standard approach vlf ac testing is preferred instead of dc high voltage testing for new and aged xlpe cables. It is commonly used in the industry for acceptance testing prior to energizing the cable and for maintenance testing programs.

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. Vlf testers are smaller and more practical than ac testers but output the same amount of power as a 50 hz mains device. There are no rules of thumb to be used. 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.

The cable tests described below are to be carried out after. Vlf cable test voltages and time durations are set by ieee standard 400 2 2013. Vlf testing uses very low frequencies as part of an ac cable maintenance routine.