IEEE 400.1:2007 pdf free download

IEEE 400.1:2007 pdf free download.IEEE Guide for Field Testing of Laminated Dielectric, Shielded Power Cable Systems Rated 5 kV and Above with High Direct Current Voltage.
4.1 Test precautions
The following precautions should be considered when performing tests with high dc voltage in the field:
All components require de-energizing and solid grounding before testing. Checking with a reliable oItage indicator that responds to alternating current (ac) and dc voltage is recommended. While the indicator is in contact with each component and indicates no voltage, a ground connection should be applied to the component and remain attached at all times except when the test voltage is being applied. All unenergized metallic parts in the vicinity of the high- voltage connections should always remain grounded.
— All cable termination ends as well as all connecting leads of components being tested require guarding from accidental contact by such means as barriers, enclosures, or a watchman at all points. The cable ends require separation from all elements not to be subjected to test and by distances at least 0.25 cm/kV (0.1 inikV) of test potential for voltages up to 100 kV and at least 0.5 cni/kV (0.2 in/kV) for higher test voltages. Please note that the test electrode geometry has a great influence on the safety clearances. The values recommended in this paragraph are only for conditions where high-voltage and ground electrodes arc smooth and unitbrm and where high- voltage connections are made with round conductors of adequate size to avoid corona. If the test connections are not smooth, larger clearances should be provided.
Breakdown or terminal flashover may generate traveling waves up and down the cable that can be of a magnitude great enough to cause degradation of the insulation of the cable or accessories or breakdown of the insulation. Consideration should he given to the installation of suitable rod gaps according to IEEE Std 4 for dc voltages to provide protection. A damping resistor rated for the voltage and energy of the cable can be installed in the series circuit to reduce oscillations and reflection voltages.
— For circuits with open-circuit (split) shields, the shield gaps should be short circuited (jumpered connection), and this jumper conductor connected to ground. Surge protectors should be disconnected and grounded. Grounding in this manner reduces overvoltages on gap insulation and surge protectors in the event of a test failure.
High direct voltage field-testing of cable systems involves all of the concerns nonnally associated with working on energized circuits, as well as several unique concerns that must be addressed. Cable circuits will nonnally have one or more ends remote from the location of the test equipment and the test operator. These ends must be cleared and guarded to ensure the safety of personnel. Reliable voice communication should be established between all such locations and the test operator.