Estimating the Impact of VLF Frequency on Effectiveness of VLF Withstand Diagnostics
نویسنده
چکیده
Hipot or voltage proof tests have long been used to assure the health of cable systems in the factory and when commissioning. A recent concern with this approach is that there is no way to judge if the effect of dropping VLF frequency (required to test long lengths) has a significant and deleterious impact on the effectiveness of a Simple Withstand Test. This paper shows how this problem has been practically addressed with both Laboratory and Utility based studies. Both of these approaches conclude that there is no deleterious impact on the effectiveness of VLF testing at the lower end of the frequency band.
منابع مشابه
On the altitude of the ELF/VLF source region generated during beatwave HF heating experiments
[1] Modulated high frequency (HF, 3–10 MHz) heating of the ionosphere in the presence of the auroral electrojet currents is an effective method for generating extremely low frequency (ELF, 3–3000 Hz) and very low frequency (VLF, 3–30 kHz) radio waves. The amplitudes of ELF/VLF waves generated in this manner depend sensitively on the auroral electrojet current strength, which varies with time. I...
متن کاملVery low-frequency blood pressure variability depends on voltage-gated L-type Ca2+ channels in conscious rats.
The mechanisms generating high- frequency (HF) and low-frequency (LF) blood pressure variability (BPV) are reasonably well understood. However, little is known about the origin of very low-frequency (VLF) BPV. We tested the hypothesis that VLF BPV is generated by L-type Ca(2+) channel-dependent mechanisms. In conscious rats, arterial blood pressure was recorded during control conditions (n = 8)...
متن کاملVortical surf zone velocity fluctuations with 0(10) min period
[1] Observations of velocity fluctuations with periods between about 4 and 30 min, thus longer than infragravity waves and referred to as very low frequency (VLF) surf zone motions, are described and compared with numerical simulations. The VLF motions discussed here exclude instabilities (generated by the wave‐driven alongshore current velocity shear) that occur in the same frequency range by ...
متن کاملELF/VLF wave generation using simultaneous CW and modulated HF heating of the ionosphere
[1] Experimental observations of ELF/VLF waves generated using the dual‐beam heating capability of the High frequency Active Auroral Research Program (HAARP) HF transmitter in Gakona, Alaska, are compared with the predictions of an ionospheric HF heating model that accounts for the simultaneous propagation and absorption of multiple HF beams. The model output is used to assess three properties ...
متن کاملتاثیر کنترل گلایسمیک و مدت ابتلا به بیماری دیابت بر تغییر پذیری ضربان قلب(HRV) در مردان دیابتی مبتلا به نوروپاتی محیطی
Background & Aims: Type 2 diabetes is commonly associated with autonomic neuropathy. The aim of the present study was investigated the impact of glycemic control and disease duration (DD) on autonomic nervous function in Type-2 Diabetic Neuropathy Men by analysis of their heart rate variability (HRV). Materials & Methods: fifty-three Man with diabetes and peripheral neuropathy were recru...
متن کامل